schneider impulse relay for 3 phase switch all

[mortenlund]

Hi all

I am new to this forum and hope this is right placed and of interest. I would like to make a setup with one or more impulse relays, controlled with one pushbuttom. It should make it possible to switch off 3 circuit breakers in the house cabinet, all on different phases.
Schneider makes one impulse relay with 4 no contacts in one body for 16 amps. Each circuit breaker in my house is a 10 amp, so 3 x 10 amp.

It is also possible instead of one 4 pole relay, to control 3 separate relays with 1 or 2 poles each, from one pushbutton - but then 2 of them will be controlled by a phase that is not the one running thru them.

I am in doubt about several things.

1 Should I break the neutral too?
2 If the relay is rated for 16 amp, is it 16 amp on each pole?
3 Is it preferrable to use the one body solution with 4 poles, over 3 separate relays - which if unlucky can get out of sync - if one of them misses a step?

Additional info: It is a small home. The 3 circuit breakers in my home controls lighting and outlets only. There are no heavy maschinery or large motors. There are 16 amp circuit breaker for the oven, but is not included in this setup, also refrigirator and other minor survailance equipment is left out. It is meant make it easy to switch off everything meaningful when leaving the house with one button. I prefer impulse relay over contactor because of power savings.
Power is 3 x 230 V to neutral and 400 V phase to phase. 50 Hz. Cabinet is with din rail mounting. Country Denmark.

.
Please, any advice is very appreaciated.

 

[davesparks]

I would install a contactor for each of the three circuits and then control the 3 contactors from the one impulse relay.

 

[pc1966]

As above, because they are 3 distinct circuits, not 3 phases of one supply, it makes more sense and is safer to have each switched separately. That also allows you an easier option in the future should you decide on differing switching policies per circuit.

As for switching the neutral, I don't know the regulations in Denmark to be able to comment. One thing that is absolutely certain is you should under no circumstance combine the neutrals for switching. If they are to be switched, they should be switched simultaneously with the corresponding line/phase conductor (i.e. using 3 * double-pole contactors, one for each L & N set).

Here in the UK it is normal for over current protection and functional switching to be in the line only, but we also have a history of a very "strong" neutral as always being close to Earth potential and verified as so as part of any testing. In France I have heard it is a requirement for protection to switch both.

 

[mortenlund]

As above, because they are 3 distinct circuits, not 3 phases of one supply, it makes more sense and is safer to have each switched separately. That also allows you an easier option in the future should you decide on differing switching policies per circuit.

As for switching the neutral, I don't know the regulations in Denmark to be able to comment. One thing that is absolutely certain is you should under no circumstance combine the neutrals for switching. If they are to be switched, they should be switched simultaneously with the corresponding line/phase conductor (i.e. using 3 * double-pole contactors, one for each L & N set).

Here in the UK it is normal for over current protection and functional switching to be in the line only, but we also have a history of a very "strong" neutral as always being close to Earth potential and verified as so as part of any testing. In France I have heard it is a requirement for protection to switch both.

Thanks for you extensive reply. I will certainly switch independently each circuit - and for good measures, both phase and neutral, in 3 independent relays. Thanks for making this clear.

But why not just use 3 impulse relays dobbelt pole? The power saving is around £ 20 or more here in Denmark per year - over a contactor witch has to be pulling most of the time?

Again - thanks for answer.

 

[DPG]

Does your relay system meet the requirements of isolating the generator from the incoming supply?

 

[davesparks]

Does your relay system meet the requirements of isolating the generator from the incoming supply?

What generator?

 

[davesparks]

Thanks for you extensive reply. I will certainly switch independently each circuit - and for good measures, both phase and neutral, in 3 independent relays. Thanks for making this clear.

But why not just use 3 impulse relays dobbelt pole? The power saving is around £ 20 or more here in Denmark per year - over a contactor witch has to be pulling most of the time?

Again - thanks for answer.

If the current rating of the impulse relays is adequate then yes you can use them.

 

[DPG]

What generator?

Apologies, I seem to have confused this with another thread!

 

[pc1966]

But why not just use 3 impulse relays dobbelt pole?

As @davesparks has said you can provided they have adequate switching capacity.

Take note though that if they say "16A" for example, usually that is for resistive switching (simple heaters, etc) which is the easiest of all. You have to check the de-rating to cope with loads with a high inrush (e.g. filament lamps, halogen heaters, electronic power supplies such as LED drivers or PC/TV, etc) or those that trigger an arc on opening (inductive loads such as motors, which can also have a high inrush...).

In the past the latching relays I have used are only 10A or so resistive and were not rated for the 650W of LED floodlighting (which is only 2.8A by simple computation).

TL;DR Read the impulse relay specification very carefully to make sure its rating matches not just the circuit load, but also the type of loading.

 

[mortenlund]

If the current rating of the impulse relays is adequate then yes you can use them.

I have figured it out, ordered 4 pole impulse relays from Siemens - 16 amp. Hope it will be as good as thought. Often reality does not equal dream. But learning is also positive.