Online Fotos: Win­fried Nrenberg/Picture Press OnlineA trans­par­ent plas­tic win­dow on the case of the machine LR 604805 from LEGRAND allows you to des­ig­nate the pro­tect­ed cir­cuit. OnlineAuto­mat­ic switch “Brown­ie” VA 63 from SCHNEIDER OnlineAuto­mat­ic from ABB. The trans­par­ent case shows the inter­nals: release spring, bimet­al plate and elec­tro­mag­net


OnlineSec­tions of DIN-peek for instal­la­tion of mod­ules. Rails are installed in the chas­sis of the elec­tri­cal pan­el hous­ing Online Fotos: Win­fried Nrenberg/Picture Press
An exam­ple of installing an elec­tri­cal pan­el in an apart­ment: a built-in cab­i­net is mod­est­ly “hid­den behind a screen”, but access to it is not lim­it­ed in any way


OnlineDif­fer­en­tial machines: DA 7786 from LEGRAND, “Brown­ie” and Mul­ti 9 Vigi from SCHNEIDER elec­tric belong to the most com­mon cat­e­go­ry C in every­day life


OnlineResid­ual cur­rent devices “ASTRO-UZO”: two-pole and four-pole


OnlineTwo-pole RCDs F 362 (ABB) and LR 602 136 (LEGRAND) open the phase and neu­tral con­duc­tors OnlineA four-pole resid­ual cur­rent device (for a three-phase net­work) from “ASTRO-UZO” shows the val­ue of the leak­age cur­rent at a giv­en time OnlineSin­gle-phase sin­gle-tar­iff elec­tric meter SO-505 (LEMZ) in a trans­par­ent case. The most com­mon elec­tric meter installed today, installed in most apart­ments OnlineThe sin­gle-phase sin­gle-tar­iff elec­tric meter TsE 6807 B (“Ener­gomera”) is designed for a more mod­ern DIN rail mount OnlineElec­tric cab­i­net from SCHNEIDER, equipped with mod­ules of the “Domovoy” series and an elec­tric meter “Ener­gomera”. All inter­nal con­nec­tions are cov­ered with a pro­tec­tive pan­el or plas­tron OnlineHinged elec­tri­cal cab­i­net for 6 mod­ules with a translu­cent plas­tic door from SCHNEIDER. ATthe door can be locked OnlineABB switch­board with DIN-rail mount­ed pro­tec­tive device mod­ules. The front cov­er plate is con­ven­tion­al­ly cut out to show the dif­fer­ent col­ored con­nect­ing con­duc­tors and mount­ing rails installed in the chas­sis of the switch­board hous­ing. OnlinePlas­tic cab­i­net (ABB) for 6 mod­ules. ATthe cab­i­net is pro­vid­ed with a place for instal­la­tion on the screws of a stan­dard elec­tric meter SO-505 (Europe). The door with a rub­ber seal allows you to install it in small coun­try hous­es OnlinePlas­tic cab­i­net built into a wall niche for mount­ing 12 mod­ules on DIN rails with two translu­cent doors. An inter­est­ing com­bi­na­tion of two small elec­tri­cal cab­i­nets into one com­mon unit OnlineMet­al door STJ BL 514 D for elec­tri­cal cab­i­net mod­el UK-510 (ABB). The cus­tomer can choose any col­or from the pro­posed range accord­ing to the com­pa­ny’s cat­a­log OnlineDoor BL 533 D for cab­i­nets of the UK-530 series from ABB is made in the form of a frame for a pic­ture. The col­or of the frame is cho­sen at the request of the cus­tomer from the vari­ety offered by the com­pa­ny’s cat­a­log Online Fotos: Win­fried Nrenberg/Picture Press OnlineABB BL 532 D Art-line door for UK-530 cab­i­nets. A wide vari­ety of mod­ern shapes and col­ors allows them to be used in any inte­ri­or with­out vio­lat­ing the over­all com­po­si­tion­al solu­tion. OnlineDoor BL 521 D mod­el UK-520 (ABB). The design of the door in the form of a pic­ture frame makes it easy to update the appear­ance of the elec­tri­cal cab­i­net using a vari­ety of col­ored inserts, for exam­ple, under new wall­pa­per in an apart­ment after ren­o­va­tion

Since the inven­tion of the elec­tric light bulb, elec­tri­cal engi­neer­ing has been advanc­ing by leaps and bounds. Today we can­not imag­ine life with­out elec­tric­i­ty. BUT­be­cause it, in addi­tion to com­fort and con­ve­nience, car­ries a threat. The dan­ger, first of all, is asso­ci­at­ed with the pos­si­bil­i­ty of elec­tric shock to peo­ple, sec­ond­ly- with fires that occur due to mal­func­tion­ing elec­tri­cal equip­ment and wiring, not to men­tion the fail­ure of expen­sive house­hold appli­ances. But all this can be avoid­ed if com­pe­tent­ly and in a time­ly man­ner to take care of pro­tec­tion mea­sures.

Do not think that only a neg­li­gent elec­tri­cian is capa­ble of get­ting under volt­age. Each of us can get an elec­tric shock, and for this it is not at all nec­es­sary to climb into the switch­board or break the wires. A sen­si­tive blow is easy to get by touch­ing famil­iar house­hold appli­ances- fridge, wash­ing machine andt.e. If the insu­la­tion of the cur­rent-car­ry­ing wire is bro­ken, the body of the elec­tri­cal appli­ance may be ener­gized. Andif it is not ground­ed, if you touch this device, an elec­tric shock will almost cer­tain­ly strike. So, in the inter­ests of elec­tri­cal safe­ty (your own and your home), you need, first­ly, to take care of ground­ing.

Sec­ond­ly, tra­di­tion­al cir­cuit break­ers, whose prog­en­i­tors were plugs, save from over­load­ing the net­work as a result of turn­ing on a large num­ber of elec­tri­cal appli­ances and a short cir­cuit (this is already an extreme case).

Final­ly, the most impor­tant ques­tion is how to pro­tect your­self from seri­ous injury if you touch a live con­duc­tor, and God for­bid, in a damp room. And­how to avoid a fire caused by elec­tric leak­age. Here, spe­cial resid­ual cur­rent devices (RCDs) come to the res­cue, which rec­og­nize the slight­est cur­rent leak­age and inter­rupt the pow­er sup­ply to the entire apart­ment or a sep­a­rate cur­rent-car­ry­ing wire.

The devices list­ed above, ground­ing and a manda­to­ry meter (with­out it, the ener­gy com­pa­ny will not sup­ply volt­age) are mount­ed in the elec­tri­cal pan­el installed today in all apart­ments (or stair­wells) and cot­tages. The cost of “stuff­ing” such a lock­er with the max­i­mum con­fig­u­ra­tion of the home with elec­tri­cal appli­ances and tak­ing care of their ser­vice­abil­i­ty and one’s own health can be hun­dreds of dol­lars. Sav­ing on safe­ty is often much more expen­sive, so in this review we set out to intro­duce you to the full range of tools and devices that resist elec­tri­cal dan­ger.


As we have already said, ground­ing is the basis for ensur­ing elec­tri­cal safe­ty. ATide­al case for each appli­ance rat­ed for 220In, whether it’s a table lamp or a TV, three con­duc­tors must fit: phase, zero and pro­tec­tive. This solu­tion has become com­mon­place and is increas­ing­ly replac­ing the out­dat­ed two-wire con­nec­tion scheme. Phase con­duc­tor (L), or in every­day life a phase,- this is a work­ing con­duc­tor that is ener­gized and sup­plies the con­sumer. It must be sup­ple­ment­ed by a zero con­duc­tor, in a dif­fer­ent way- work­ing zero (N), or “neu­tral”. Zero pro­tec­tive con­duc­tor, or “pro­tec­tive earth­ing” (PE), pro­vides ground­ing of the net­work. For it, as a rule, a wire in yel­low-green striped insu­la­tion is used.

If your house was built after 1998–1999, then, most like­ly, a pro­tec­tive zero con­duc­tor PE has already been stretched to the sock­ets, or, as the “spe­cial­ists” say, a pro­tec­tive zero has been wound up. ATIn this case, groups of wires are laid from the switch­board to your apart­ment: for light­ing- 2 con­duc­tors, phase and neu­tral (L+N); group for sock­ets- 3 con­duc­tors (L+N+PE); group on the elec­tric stove- 3 con­duc­tors (L+N+PE). That is, 3 wires must go to the sock­ets, and the neu­tral and pro­tec­tive (N and PE) in no case can be con­nect­ed to a com­mon ter­mi­nal on the shield.

If you live in a house of an ear­li­er con­struc­tion, from the sev­en­ties and eight­ies, there may not be a pro­tec­tive zero on the sock­ets. FROMon the oth­er hand, the floor plate is usu­al­ly ground­ed. There­fore, it makes sense to invite an elec­tri­cian from the local DEZ. He knows for sure whether there is a reli­able ground in the shield, and if nec­es­sary, he can lay an addi­tion­al zero pro­tec­tive con­duc­tor to one of the sock­ets, for exam­ple, to con­nect a wash­ing machine.

So, in a city apart­ment with pro­tec­tive ground­ing, it is more or less clear. BUTHere, the own­ers of their own home have some­thing to break their heads over.

As a rule, the sup­ply to such hous­es is car­ried out through an over­head pow­er line, and the shield in the house is not ground­ed (and this must be done!). ATIn this case, it is com­plete­ly unac­cept­able to use the incom­ing zero work­ing N‑conductor as a pro­tec­tive PE-con­duc­tor. In the event of a break in the over­head pow­er line (for exam­ple, a tree has fall­en), the neu­tral con­duc­tor (N) may be ener­gized. Then the same volt­age val­ue will appear on the pro­tec­tive con­duc­tor PE (to which, in the­o­ry, the cas­es of all house­hold elec­tri­cal appli­ances are con­nect­ed), and from a pro­tec­tive one it will turn into a dead­ly one! There­fore, it is espe­cial­ly impor­tant to car­ry out ground­ing in the cot­tage. What is need­ed for this?

First of all, you can use nat­ur­al ground­ing con­duc­tors, which can become:

water and oth­er met­al pipelines laid in the ground, with the excep­tion of pipelines of flam­ma­ble liq­uids, flam­ma­ble and explo­sive gas­es and mix­tures, sew­er­age and cen­tral heat­ing;
well cas­ing pipes;
met­al and rein­forced con­crete struc­tures of build­ings and struc­tures in con­tact with the ground.

If there is such an oppor­tu­ni­ty, it is good to with­draw from them. The out­let is equipped only by weld­ing- this is the only way to ensure the required cross-sec­tion­al area. ATas a ground­ing con­duc­tor, use strip steel with a cross sec­tion of at least 48mm2 with a thick­ness of at least 4mm or steel angle with a shelf thick­ness of at least 2.5mm. A strip or a cor­ner is laid in a room where it is nec­es­sary to make a ground loop from a steel strip with a cross sec­tion of at least 24mm2 and a thick­ness of at least 3mm. Anoth­er option: a bolt is weld­ed to the strip (cor­ner), a cop­per con­duc­tor is attached to it (from 2.5mm2), which will be the pro­tec­tive PE con­duc­tor.

If the house is wood­en, and there are no pipelines or wells near­by, you need to make an arti­fi­cial ground elec­trode. This is a very dif­fi­cult task. In addi­tion to the fact that a large amount of soil will have to be trans­ferred, it will be nec­es­sary to addi­tion­al­ly car­ry out some cal­cu­la­tions and mea­sure­ments of the elec­tri­cal resis­tance of the soil on site. It is bet­ter to entrust all this work to qual­i­fied spe­cial­ists.

Orga­ni­za­tion of pro­tec­tive ground­ing- this is only the first step in ensur­ing the elec­tri­cal safe­ty of a per­son and a home. The next step in the orga­ni­za­tion of pro­tec­tion can be cir­cuit break­ers, or, as they are more com­mon­ly called, automa­ta.

Circuit breakers

To begin with, we note that sock­ets, switch­es, automa­tion, meters and much oth­er house­hold elec­tri­cal equip­ment are pro­duced in a wide range by a num­ber of com­pa­nies. To name just a few: ABB, AEGKopp, BuSch-Jaeger Elec­tro, Siemens (Ger­many), Schnei­der Elec­tric, Legrand (France), “ASTRO-UZO” (Europe) andothers

Man­u­fac­tur­er ven­dor code Num­ber of poles Rat­ed cur­rent, A Short cir­cuit cur­rent, kA price, rub.
ABB S231RC16 sin­gle pole 16 4.5 129
LEGRAND 6019 opens
2 con­duc­tors (L+N)
16 6 302.6
604805LR sin­gle pole 16 6 110
SCHNEIDER ELECTRIC SE 24403 Mul­ti 9 sin­gle pole 16 6 199
SIEMENS 5SQ21700KA10 sin­gle pole 16 4.5 125.3
“INTERELECTROKOMPLEKT” Auto­mat­ic switch sin­gle pole 16 4.5 45.5
AEG Auto­mat­ic switch sin­gle pole 16 6 129
BUSCH-JAEGER ELECTRO Hager MS140 sin­gle pole 40 6 107
CORR RCD sin­gle pole 16 6 130

Auto­mat­ic switch­es (auto­mat­ic devices)- the most wide­ly known and famil­iar pro­tec­tive device. Designed to pro­tect the cir­cuit from short cir­cuits and over­loads. They replaced burnt plugs- one-time prog­en­i­tors of elec­tri­cal pro­tec­tion- 20–30 years ago. Today, machines are equipped with a spe­cial actu­a­tor- a release that direct­ly opens the elec­tri­cal cir­cuit.

Most of the mod­ern house­hold cir­cuit break­ers on the Euro­pean mar­ket- com­bined. They have an elec­tro­mag­net­ic and ther­mal release and can simul­ta­ne­ous­ly pro­tect against net­work over­loads and short cir­cuits (short cir­cuits). Elec­tro­mag­net­ic release- this is an elec­tro­mag­net capa­ble of pro­tect­ing the cir­cuit from a short cir­cuit when the cur­rent instant­ly increas­es to crit­i­cal val­ues, 5–10 times (cat­e­go­ry C) exceed­ing the nom­i­nal val­ues. In this case, the machine must turn off the cir­cuit in a time of about 0.01 sec­onds. Ther­mal release- a bimetal­lic plate that changes its shape when heat­ed. This ele­ment pre­vents crit­i­cal over­loads, accom­pa­nied by a sig­nif­i­cant heat­ing of the con­duc­tors, the braid of which can ignite. An auto­mat­ic machine with such a mech­a­nism, at a load exceed­ing the nom­i­nal val­ue by 13%, must turn off the cir­cuit with­in an hour.

What is the nature of the danger of electric current and the consequences of defeat by it for a person?

The dan­ger of expo­sure to elec­tric cur­rent depends on two fac­tors:

the time of cur­rent flow through the human body;
cur­rent strength.

These fac­tors are not relat­ed to one anoth­er, the elec­tri­cal injury will be more or less, depend­ing on the mag­ni­tude of each of them.

To assess the degree of dan­ger, the curves of change of two para­me­ters are deter­mined- the mag­ni­tude of the cur­rent strength and expo­sure time. Graphs are shown in the fig­ure.

Haz­ard zones for humans depend­ing on the phys­i­o­log­i­cal effects of elec­tric cur­rent:

AC1- usu­al­ly no reac­tion;
AC2- no dan­ger­ous phys­i­o­log­i­cal effects;
AC3- reversible car­diac arrhyth­mias, increas­ing with increas­ing cur­rent and expo­sure time;
AC4- Phys­i­o­log­i­cal dis­or­ders such as car­diac arrest, res­pi­ra­to­ry arrest, severe burns.

The mag­ni­tude of the dan­ger­ous cur­rent flow­ing through the human body is esti­mat­ed as fol­lows: with direct con­tact with live parts at a volt­age of about 220The cur­rent deter­mines the resis­tance of the human body, con­di­tion­al­ly equal to 1000 ohms (with the most unfa­vor­able option along the arm / leg flow path). Then the pass­ing cur­rent is 220 mA. This is a seri­ous elec­tri­cal injury requir­ing imme­di­ate hos­pi­tal­iza­tion.


Fire haz­ard. Not only peo­ple are exposed to the dan­gers of elec­tric cur­rent, but also equip­ment. It pos­es a risk of fire. For exam­ple, a cur­rent of 500 mA flow­ing through com­bustible mate­ri­als for some time can cause them to ignite. ATIn every elec­tri­cal instal­la­tion, there are always cur­rent leak­ages, which can vary sig­nif­i­cant­ly depend­ing on the con­di­tion of the equip­ment, its oper­at­ing time, envi­ron­men­tal con­di­tions andt.e. Leak­age cur­rents pass in the met­al parts of the struc­ture (pipes, beams and oth­er ele­ments) and heat them up, which can cause a fire. More than a third of all fires occur due to the igni­tion of elec­tri­cal wiring.

ATde­pend­ing on the oper­a­tion char­ac­ter­is­tic, cir­cuit break­ers are divid­ed into groups: B, C and D. To pro­tect net­works in the hous­ing and com­mu­nal sec­tor, cat­e­go­ry C devices are usu­al­ly used, since they are uni­ver­sal and designed for short-cir­cuit cur­rents that are 5–10 times above the rat­ed cur­rent. Cir­cuit break­ers of this cat­e­go­ry can also be used in cir­cuits sup­ply­ing elec­tric motors, pumps andt.e. Less com­mon­ly used in every­day life are more sen­si­tive automa­tons of cat­e­go­ry B. They oper­ate at cur­rents 3–5 times high­er than the nom­i­nal val­ue, and are used in elec­tron­ics.

Devices of both cat­e­gories are issued in denom­i­na­tions of 6, 10, 13, 16, 20, 25, 32, 40, 50 and 63A. It is impor­tant to note that the rat­ing of the machine is select­ed based on the per­mis­si­ble cur­rent load of the con­duc­tors. That is, the com­pli­ance of the char­ac­ter­is­tics of the machine and the cross sec­tions of the con­duc­tors with the pow­er con­sump­tion that is includ­ed in the elec­tri­cal instal­la­tion project of a house or apart­ment must be achieved.

There are one‑, two- and three-pole switch­es. The first ones are set to open the phase (live wires), and they are most often used in apart­ments and hous­es. Less com­mon­ly used are bipo­lar, which turn off not only the phase, but also the neu­tral wire. BUTthree‑, four-pole machines are designed for a three-phase con­nec­tion with a volt­age of 380B, where three ener­gized phase wires, one neu­tral wire and one pro­tec­tive wire are woven in one cable.

Com­mon mis­take- the use of an automa­ton with an over­es­ti­mat­ed trip­ping cur­rent. Actu­al­ly, this is not even a mis­take, but a vio­la­tion. For exam­ple, in an old house with dilap­i­dat­ed wiring, the sock­et pro­tects the machine at 10And, and the own­er of the apart­ment acquires a mod­ern elec­tric ket­tle with a pow­er con­sump­tion of 2.2 kW and turns it on. What’s hap­pen­ing? The machine works. The own­er, with­out hes­i­ta­tion, replaces the machine with anoth­er, with a large trip cur­rent- at 16Oh, and even 25A (what­ev­er comes to hand). After that, the machine will no longer “knock out”. But the net­work, which was not orig­i­nal­ly designed for such cur­rents, will start to work with a large over­load. Con­duc­tors will over­heat. With luck, the cir­cuit break­er will trip when a short cir­cuit occurs as a result of the melt­ing of the wire insu­la­tion. Although life shows that in such cas­es, igni­tion of the wiring occurs ear­li­er.

Mod­ern mod­els of machines are mount­ed on the so-called DIN rail, which is a mount­ing rail-bar with a width of 35mm, cor­re­spond­ing to a sin­gle inter­na­tion­al stan­dard. ATIn the res­i­den­tial sec­tor, such machines will cer­tain­ly dis­place (and are already dis­plac­ing) devices of old stan­dard sizes that are mount­ed with screws.

As already men­tioned, machines, first of all, pro­tect elec­tri­cal cir­cuits from over­loads. Trip­ping cur­rents for which the cir­cuit break­ers are designed,- from 6 to 100A. Bif a per­son touch­es a live con­duc­tor 220In a bro­ken insu­la­tion, such cur­rents may not occur. If the resis­tance of the human body is con­di­tion­al­ly tak­en equal to 1000 ohms (with the cur­rent flow path arm / leg), then the cur­rent pass­ing through the body is equal to 220 mA. For a per­son, this is a seri­ous elec­tri­cal injury, but the machine does not per­ceive this val­ue as a short cir­cuit cur­rent and does not turn off the cir­cuit. There­fore, to pro­tect a per­son from acci­den­tal elec­tric shock, anoth­er device is need­ed.- it is a pro­tec­tive shut­down device.

Residual current devices and differential automata

Their active intro­duc­tion into wide prac­tice began in the six­ties and sev­en­ties of the last cen­tu­ry all over the world, espe­cial­ly in West­ern Europe, Japan and the USA. To date, the USO- the only one of all known elec­tri­cal pro­tec­tive equip­ment that not only pro­vides pro­tec­tion for a per­son from elec­tric shock, but is also able to pro­tect against igni­tion and fires due to a mal­func­tion of elec­tri­cal wiring and elec­tri­cal equip­ment. Large­ly due to this, insur­ance com­pa­nies, when assess­ing the risk that deter­mines the sum insured, nec­es­sar­i­ly take into account the pres­ence of pro­tec­tive shut­down devices at the facil­i­ty and their tech­ni­cal con­di­tion.

Man­u­fac­tur­er Mod­el Num­ber of poles Rat­ed cur­rent, A Dif­fer­en­tial cur­rent, mA Type of price, rub.
ABB DS 941 C25 1P + N 25 thir­ty AC 1798.5
LEGRAND 7886 1P + N 16 thir­ty AC 1407
SE 19665 Mul­ti 9 1P + N 16 thir­ty AC 1936
SCHNEIDER ELECTRIC SE 11474 Brown­ie 1P + N 25 thir­ty AC 1427
SIEMENS 5SU13531KV16 1P + N 16 thir­ty AC 1075
5SU13531KV40 1P + N 40 thir­ty AC 1075
CORR MSV 1P + N 16 thir­ty AC 1669
BUSCH-JAEGER ELECTRO Hager AD007A 1P + N 16 thir­ty AC 829

Man­u­fac­tur­er Mod­el Num­ber of poles Rat­ed cur­rent, A Dif­fer­en­tial cur­rent, mA Type of price, rub.
ABB F 362 Bipo­lar 25 thir­ty AC 1198.5
F 372 Bipo­lar 25 thir­ty BUT 1866.7
LEGRAND LR 602 136 Bipo­lar 25 thir­ty AC 876
8909 Bipo­lar 25 thir­ty AC 990
SCHNEIDER SE 11450 Bipo­lar 25 thir­ty AC 906
SIEMENS 5SM13140 Bipo­lar 25 thir­ty AC 938
CORR RCD Bipo­lar 25 thir­ty AC 1243

ATon sale there are RCDs designed for two rat­ed volt­ages (the effec­tive val­ue of the volt­age at which the oper­abil­i­ty of the device is ensured)- 220 and 380B, as well as for rat­ed cur­rents of 6; 16; 25; 40; 63; 80; 100; 125A, which the device can skip for a long time. Obvi­ous­ly, the choice of the device accord­ing to the first para­me­ter depends on what volt­age you have in the net­work, while the rat­ed cur­rent is deter­mined by the pow­er con­sumed by house­hold appli­ances in the pro­tect­ed cir­cuit. An esti­mat­ed cal­cu­la­tion of pow­er con­sump­tion was giv­en in the arti­cle “Home Ener­gy”.

Rat­ed resid­ual break­ing cur­rent- this is the most impor­tant para­me­ter of the resid­ual cur­rent device for the con­sumer. FROM­from a tech­ni­cal point of view, we are talk­ing about the leak­age cur­rent strength, which caus­es the RCD to trip under spec­i­fied oper­at­ing con­di­tions (0.006; 0.01; 0.03; 0.1; 0.3; 0.5BUT). That is, when such a leak­age cur­rent occurs, the cir­cuit will instant­ly open. For wet areas- san­i­tary cab­ins, bath­rooms and show­ers,- if a sep­a­rate line is allo­cat­ed to them, it is rec­om­mend­ed to use an RCD with a trip cur­rent of 10 mA. ATin oth­er cas­es, even for street sock­ets, it is allowed to use an RCD with a trip cur­rent of 30 mA. Sep­a­rate­ly, to increase the lev­el of fire pro­tec­tion at the entrance to an apart­ment or an indi­vid­ual house, experts rec­om­mend installing an RCD with a trip cur­rent of 300 mA.

The reli­a­bil­i­ty and qual­i­ty of RCDs are deter­mined by the con­di­tion­al short-cir­cuit cur­rent- 3000, 4500, 6000, 10,000A (this para­me­ter is some­times called “short-cir­cuit cur­rent resis­tance”). The high­er the spec­i­fied val­ue, the more reli­able your resid­ual cur­rent cir­cuit break­er will be.

The principle of operation of the RCD


The phase con­duc­tor (L) and the “neu­tral” (N) pass through the K1 core in such a way that the elec­tro­mag­net­ic fields induced by them are oppo­site­ly direct­ed. Pro­vid­ed there are no leaks in the cir­cuit, these fields are equal and can­cel each oth­er out.

If a leak­age occurs, a cur­rent appears in the wind­ing of the K1 core (since the cur­rents flow­ing through the con­duc­tors N and L are not equal and their fields are not mutu­al­ly com­pen­sat­ed). The val­ue of this cur­rent is esti­mat­ed by the resid­ual cur­rent relay K2. When a cer­tain thresh­old is exceed­ed, the relay caus­es the cir­cuit to be inter­rupt­ed.

A dif­fer­en­tial device (RCD) con­stant­ly com­pares the cur­rent flow­ing through the phase wire (to the appli­ance) with the cur­rent flow­ing through the “neu­tral” (from the appli­ance). In the case when the dif­fer­ence between these cur­rents reach­es a val­ue dan­ger­ous for human life, the device turns off the sup­ply volt­age. This means that if a per­son touch­es a bare wire or a faulty elec­tri­cal appli­ance and a cur­rent flows through it to the “ground”, a cur­rent dif­fer­ence (leak­age) will appear. The device imme­di­ate­ly works and dis­con­nects the cir­cuit from the volt­age. More­over, the response time of the RCD is so short that the cur­rent does not have time to cause dam­age to health.

There are two types of dif­fer­en­tial dis­con­nect devices: AC and A. The dif­fer­ence between them lies in the sen­si­tiv­i­ty of these devices to direct cur­rent that appears in a nor­mal vari­able net­work under the influ­ence of house­hold appli­ances. RCD type AC has a spe­cial des­ig­na­tion on the case- a sinu­soid in a rec­tan­gle. It is sen­si­tive only to alter­nat­ing (sinu­soidal) leak­age cur­rent, while speed-con­trolled wash­ing machines, adjustable light sources, VCRs, com­put­ers, audio equip­ment dis­tort, rec­ti­fy the sinu­soid and are sources of pul­sat­ing cur­rent. ATUn­der such con­di­tions, an RCD of the AC type sharply los­es its sen­si­tiv­i­ty, and hence the abil­i­ty to reli­ably pro­tect a per­son from elec­tric shock. Type A devices come to the res­cue here, respond­ing to both alter­nat­ing and pul­sat­ing fault cur­rents (leak­age cur­rents with a con­stant com­po­nent). Such RCDs are 20–50% more expen­sive than AC-type RCDs, but for groups of out­lets, and for light­ing groups, it is advis­able to use them.

Resid­ual cur­rent devices of both types (AC and A) exist either in the S (selec­tive) ver­sion or in the con­ven­tion­al ver­sion. Exe­cu­tion S (type A or AC) implies oper­a­tion with a time delay. It is used when it is nec­es­sary to give addi­tion­al time for the pri­ma­ry oper­a­tion of oth­er pro­tec­tive devices or cir­cuit break­ers.

You can check the oper­a­tion of a new­ly installed or long-run­ning RCD by press­ing the “TEST” but­ton, which is on the front pan­el of most devices (in addi­tion to the on-off switch). Press­ing this but­ton arti­fi­cial­ly cre­ates a resid­ual trip­ping cur­rent. If the RCD is OK, it should trip. Man­u­fac­tur­ers rec­om­mend that this check be car­ried out month­ly. After the RCD has tripped and the mal­func­tion that caused it has been elim­i­nat­ed, the device is again brought into work­ing con­di­tion by the pow­er lever.

Pro­tec­tive dif­fer­en­tial devices can be installed in an exist­ing dis­tri­b­u­tion cab­i­net of an apart­ment- one device with a nom­i­nal val­ue of 30 mA for the entire dwelling. This option is rel­a­tive­ly cheap, but it does not allow you to deter­mine the loca­tion of the leak, and, in addi­tion, when the RCD is trig­gered, the entire apart­ment is left with­out light. A much more pro­gres­sive solu­tion, which makes sense to strive for,- instal­la­tion of sev­er­al pro­tec­tive dif­fer­en­tial devices on sep­a­rate lines. ATIn this case, the elec­tri­cal wiring is divid­ed into inde­pen­dent branch­es serv­ing var­i­ous con­sumer groups. For exam­ple, the fol­low­ing lay­out is pos­si­ble: sep­a­rate branch­es for a group of sock­ets, for light­ing, for a group of pow­er devices (wash­ing machine, elec­tric stove), a sep­a­rate branch for a bath­room and show­er.

Each group must be con­trolled by its own cir­cuit break­er and its own RCD. To do this, inde­pen­dent (start­ing from the switch­board) wires for the phase (1 to 220B or 3 by 380B), for neu­tral N and for earth PE. The pres­ence of a sep­a­rate ground wire, as we have already said, increas­es the lev­el of safe­ty.

With such detail, it is pos­si­ble to ful­ly imple­ment step­wise or selec­tive pro­tec­tion, the prin­ci­ple of which is the abil­i­ty to deter­mine exact­ly which device caused the leak and dis­able only it. The rat­ing (nom­i­nal break­ing dif­fer­en­tial cur­rent) of each sub­se­quent pro­tec­tion from the input of elec­tric­i­ty to the house is select­ed one step low­er (or even less), but it can nev­er be more! In oth­er words, if there is an RCD designed for a leak­age cur­rent of 30 mA at the entrance to the apart­ment, then the RCD intend­ed for the branch of the bath­room, kitchen or a sep­a­rate wash­ing machine should be cal­cu­lat­ed for 10 or 6 mA. If this con­di­tion is met, in a crit­i­cal sit­u­a­tion, the pro­tec­tive device clos­est to the fault will oper­ate first. For exam­ple, in the event of a mal­func­tion in the elec­tric stove, the RCD will trip in the elec­tric stove cir­cuit. All oth­er lines, includ­ing light­ing, will remain oper­a­tional. In order for the pro­tec­tion in front of the object to be guar­an­teed to work in the first place, an RCD is mount­ed on the input-dis­tri­b­u­tion device, which oper­ates with a cer­tain time delay (of the order of 0.1–0.5 sec­onds), that is, an RCD in S‑selective design.

Pro­tect­ing against leak­age cur­rents, the RCD has a nar­row spe­cial­iza­tion and is in no way capa­ble of replac­ing a cir­cuit break­er. Over­load or short cir­cuit pro­tec­tion- the pat­ri­mo­ny of the auto­mat­ic switch, which must be installed to pro­tect the elec­tri­cal cir­cuit and the dif­fer­en­tial device itself. For exam­ple, an RCD with a rat­ed oper­at­ing cur­rent of 25And it is nec­es­sary to pro­tect it with an auto­mat­ic device hav­ing a trip cur­rent of not more than 25BUT.

In order to avoid the need to pur­chase many dif­fer­ent machines and RCDs, man­u­fac­tur­ing com­pa­nies have cre­at­ed and put on the mar­ket devices with built-in pro­tec­tion against short cir­cuits and over­loads.- dif­fer­en­tial machines. This is a kind of hybrid of a cir­cuit break­er and an RCD in one hous­ing. An exam­ple of such devices are the mod­els of the Mul­ti 9 series from SCHNEIDER, RCD from KOPP, DS 941 from ABB, as well as devices from Legrand. More­over, the lat­ter even have a trans­par­ent plas­tic pock­et for easy mark­ing of the pro­tect­ed cir­cuit. The pres­ence of dif­fer­en­tial automa­ta on the mar­ket has great­ly sim­pli­fied the life of con­sumers, who now do not need to think about match­ing the elec­tri­cal para­me­ters of the RCD and the cir­cuit break­er.

The dif­fer­en­tial machine opens the elec­tri­cal cir­cuit when it is exposed to any of the three mal­func­tion fac­tors:

short cir­cuit (coils with a core react to it);
over­load cur­rent (bimetal­lic plates are trig­gered);
dif­fer­en­tial leak­age cur­rent (in this case, the mag­ne­to-elec­tric release oper­ates).

OnlineScheme of the elec­tri­cal pan­el of a typ­i­cal apart­ment using RCDs and cir­cuit break­ers 1. Shield hous­ing
2. Con­nect­ing ele­ment of zero work­ing con­duc­tors
3. Con­nect­ing ele­ment of zero pro­tec­tive con­duc­tors
4. RCD for leak­age cur­rent 30 mA
5. Cir­cuit break­ers
6. RCD for leak­age cur­rent 10 mA
7. Elec­tric­i­ty meter
8. Group cir­cuit lines

Protection against lightning and induced surges. Dischargers

over­volt­age- impulse excess of the rat­ed oper­at­ing volt­age of the net­work, pow­er surge dur­ing a light­ning strike (can reach 15 kV). Over­volt­ages and, as a result, fail­ure of elec­tri­cal wiring, equip­ment and devices, fires can occur in the net­work in the fol­low­ing cas­es:

Direct expo­sure to high-volt­age atmos­pher­ic dis­charge- at the points of a direct light­ning strike, strong cur­rents can flow in the con­duc­tive ele­ments.
Direct hit at one point. It is capa­ble of caus­ing over­volt­ages at a dis­tance of sev­er­al hun­dred meters to sev­er­al kilo­me­ters from the place of a light­ning strike. Spread­ing through pow­er grids, pipelines andt.etc., an over­volt­age impulse enters build­ings and dis­ables elec­tri­cal equip­ment.
Light­ning strike to the ground. An over­volt­age surge on a ground con­duc­tor can prop­a­gate through the ground.

ATdur­ing the oper­a­tion of elec­tric motors (in ele­va­tors of apart­ment build­ings, pumps andt.e) the appear­ance of high-volt­age dis­charges of non-atmos­pher­ic ori­gin in the net­work of the house is like­ly.

An over­volt­age between the mains and the ground can com­plete­ly dis­able the elec­tri­cal pan­el. An over­volt­age that occurs between the phase con­duc­tor and the “neu­tral” dam­ages elec­tri­cal equip­ment (audio-video equip­ment and com­put­ers). ATIn this case, the pro­tec­tive shut­down helps out when the volt­age in the net­work is exceed­ed. Devices that allow such a shut­down are called arresters (or surge sup­pres­sors). The main task of the arrester- send an over­volt­age impulse to the ground, there­fore, the instru­ment case pro­vides the pos­si­bil­i­ty of con­nect­ing a ground­ing con­duc­tor with a cross sec­tion of 10 mm² or more. Arresters are mount­ed imme­di­ate­ly behind the intro­duc­to­ry cir­cuit break­er and are nec­es­sar­i­ly con­nect­ed to the “ground” ter­mi­nal of the elec­tri­cal pan­el.

All arresters cer­tain­ly have an oper­at­ing sta­tus indi­ca­tor. After one or two oper­a­tions (light­ning strikes), devices from ABB and Schnei­der must be replaced, as indi­cat­ed by the LED indi­ca­tion on the front pan­el. ATun­like these arresters, LEGRAND devices con­sist of a base and a work­ing mod­ule. This is espe­cial­ly use­ful for four-pole arresters in a net­work designed for 380B (pro­tec­tion of three phas­es and earth), since it becomes pos­si­ble to replace only one of the four mod­ules.

Among the devices of Euro­pean man­u­fac­tur­ers, arresters of the OPN-12 / 0.4 brand of the ASTRO-UZO com­pa­ny are known. Designed for max­i­mum cur­rent up to 10 kA and volt­age up to 1200B, they allow you to reduce the over­volt­age to a safe val­ue, at which there is no break­down of the insu­la­tion of elec­tri­cal equip­ment.

Helpful Hints

Don’t skimp on the con­duc­tor. Prop­er­ly select­ed cop­per cable (wire) will not bring any sur­pris­es- 50 years you can sleep peace­ful­ly.
It is absolute­ly unac­cept­able to con­nect direct­ly cop­per and alu­minum, use mount­ing blocks.
It is impos­si­ble to save on the equip­ment of pro­tec­tion. A good machine, Ouzo or dif­fer­en­tial machine can­not be cheap.
Avoid con­nect­ing strand­ed con­duc­tors under the screw (for exam­ple, in meters).
When using a three-phase net­work to pow­er the equip­ment, an indi­vid­ual work­ing zero should be laid on each phase.
Breaks in the ground line must not be allowed. All con­nec­tions must be made only in par­al­lel, with­out dam­ag­ing the main ground­ing line.

A few words about electricity meters

As a rule, for­eign man­u­fac­tur­ers that pro­duce devices for mount­ing on a DIN rail nec­es­sar­i­ly include elec­tri­cal mea­sur­ing instru­ments in their prod­uct range.- amme­ters, volt­meters and elec­tric meters. How­ev­er, before pur­chas­ing a brand­ed elec­tric­i­ty meter that you like, you need to get it from your local elec­tric­i­ty sup­pli­er office.- “Ener­gos­byt” con­sent to its instal­la­tion in your apart­ment or house. BUTsince each new­ly installed elec­tric meter goes to the bal­ance of such an orga­ni­za­tion, it exer­cis­es con­trol over it, assumes the respon­si­bil­i­ty for its repair and main­te­nance, then all mod­els of elec­tric meters, Euro­pean and import­ed, must be cer­ti­fied and only after its suc­cess­ful com­ple­tion are rec­om­mend­ed for wide­spread use.

ATAt present, domes­tic elec­tric meters “INCOTEKS” are wide­ly rep­re­sent­ed on the mar­ket (Kazakhstan).world), LEMZ (city ofPeters­burg), Mytishchi plant andetc. They are afford­able and mount­ed in the shield in the tra­di­tion­al way- on screws. But to date, mod­ules installed on a DIN rail have prac­ti­cal­ly replaced all oth­ers. Andit would be very con­ve­nient to have a DIN-rail-mount­able elec­tric­i­ty meter, for exam­ple, the cer­ti­fied DAN 2902 Delta mod­el, which ABB pro­duces at the Metron­i­ca plant in the world. I would like to note that among Euro­pean elec­tric­i­ty meters there are those installed on a DIN rail. This is, say, a sin­gle-phase mod­el TsE 6807 B‑1 and a three-phase meter TsE 6807 B‑2 of the Ener­gomera Stavropol plant.

Man­u­fac­tur­er Mod­el Descrip­tion price, rub.
ABB BL 531D Alu­minum col­or with pic­ture frame 8601
STJ BL 514D anthracite metal­lic 1950
BL 532D Art line door 8754
BL 533D Bur­gundy metal­lic with pic­ture frame 2158
SCHNEIDER SE 10331 Opaque, for wall cab­i­net “Brown­ie” 207.6
SE 10305 Trans­par­ent, for built-in cab­i­net “Brown­ie” 207.6

Man­u­fac­tur­er Mod­el Descrip­tion price, rub.
ABB DAN 2502 Dual rate, class 2, 220/400 V (65 A) 12943
DAN 2902 Sin­gle tar­iff, class 2, 220/400 V (65 A) 10200
LEMZ SO-505 Sin­gle-phase, sin­gle tar­iff, class 2, 10–40 A 645
SO-EE6706 Sin­gle-phase sin­gle tar­iff, class 2, 10–40 A, trans­par­ent case 645
“ENERGOMERA” CE 68 07 B DIN-rail, sin­gle-phase, sin­gle-rate, 5–50 A 1260
CE 6803V DIN-rail, three-phase, sin­gle-rate, 10–100 A 2628
Mytishchi plant CE 6807 B‑1 Sin­gle-phase, sin­gle-rate, class 2, 50 A 975
CE 6807 B Sin­gle-phase, two-rate, class 2, 50 A 1178
SA4-I678 Three-phase, sin­gle tar­iff, 50–100 A 2309


And now, final­ly, we have come to the moment when the scheme for pro­tect­ing the elec­tri­cal net­work of your home has already been select­ed, all pro­tec­tive mod­ules have been pur­chased, their num­ber and mod­els have been deter­mined. Now the devices that make up the cir­cuit you built need to be installed (hid­den) some­where. To do this, SCHNEIDER, SIEMENS, ABB and some oth­ers pro­duce plas­tic shield cas­es that pro­vide high user safe­ty and fit per­fect­ly into the inte­ri­or of an apart­ment or house. For exam­ple, ABB sup­plies the Euro­pean mar­ket with a plas­tic case mod­el 13204, designed for 12 mod­u­lar blocks, in which a spe­cial place is pro­vid­ed for mount­ing the Euro­pean elec­tric meter mod­el SO-505 on the screws. The hous­ings of all shields are made of self-extin­guish­ing plas­tic, which does not con­duct elec­tric­i­ty. The design of the hous­ings is such that it com­plete­ly elim­i­nates acci­den­tal access to live parts.

For ease of instal­la­tion of equip­ment in the switch­boards, uni­fied com­po­nents are used:

DIN rails on which all equip­ment is mount­ed;
ter­mi­nal bars- for con­ve­nience of join­ing of con­duc­tors;
comb tav­erns- for ease of switch­ing of sev­er­al devices installed in a row;
side plugs- pro­tec­tive caps used to iso­late open live parts;
pro­tec­tive and dec­o­ra­tive pan­els that com­plete­ly cov­er the instal­la­tion wires inside the cab­i­net body.

The enclo­sures of the shields can be sup­plied in hinged and built-in ver­sions. Hinged cas­es are mount­ed on a wall and are used, as a rule, for open elec­tri­cal wiring. Recessed shields are installed in a wall niche and are usu­al­ly used for hid­den wiring. Tocase you can choose a trans­par­ent or mat­te door and mor­tise lock. A huge vari­ety of dec­o­ra­tive doors for lock­ers will not leave any­one indif­fer­ent.

When choos­ing a switch­board, you should take into account that man­u­fac­tur­ers rec­om­mend- to cre­ate favor­able work­ing con­di­tions for elec­tri­cal equip­ment- pro­vide up to 30% free vol­ume inside the box. In addi­tion, in the future, this unoc­cu­pied space makes it pos­si­ble to install some addi­tion­al equip­ment (dur­ing the mod­ern­iza­tion of the pow­er grid).

Man­u­fac­tur­er Mod­el Num­ber of mod­ules Descrip­tion price, rub.
SCHNEIDER SE 10322 Brown­ie 24 Hinged, with­out door 390
SE 13942 Mini Prag­ma 24 Built-in wardrobe, trans­par­ent door 800.6
SE 13912 Mini Prag­ma 24 Wall cab­i­net, opaque door 865.6
SIEMENS 8GB11031 36 Built-in, for hid­den wiring 1590
8GB13011 12 Mount­ed, for open wiring 596.7
8GB13031 36 Mount­ed, for open wiring 1536.8
ABB 12044 24 Recessed, with translu­cent hor­i­zon­tal door 927
12742 2–4 Wall-mount­ed box with a translu­cent hor­i­zon­tal door, dust- and mois­ture-proof, for out­door instal­la­tion 384.7
13204 12 Wall cab­i­net, trans­par­ent door, place for CO-505 counter 1363
“interkom­plekt” ShchRN-12z 12 Hinged met­al cab­i­net with a lock 397.5

Towho to contact?

Recent­ly, many com­pa­nies have appeared that are engaged in the instal­la­tion of elec­tri­cal equip­ment and per­form the entire range of elec­tri­cal work. When con­clud­ing an agree­ment with such a com­pa­ny, you should pay atten­tion to the avail­abil­i­ty of a license con­firmed by Energ­onad­zor.

To con­nect house­hold appli­ances, it makes sense to con­tact the sell­er’s ser­vice cen­ter.

BUT­to lay a zero pro­tec­tive con­duc­tor when con­nect­ing, for exam­ple, a new wash­ing machine, with­out hav­ing in mind the com­plete mod­ern­iza­tion of the elec­tri­cal wiring in the apart­ment, you can invite a rep­re­sen­ta­tive of the ser­vice orga­ni­za­tion (DEZ, ZhEK andt.d.).

The edi­tors would like to thank the CROCUS-TRADE com­pa­ny and the accred­it­ed rep­re­sen­ta­tive office of LEGRAND in EU for their help in prepar­ing the mate­r­i­al.

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