4 Pole or 3 Pole panel disconnect (europe)

[DaveRosser]

I am trying to determine whether you are required to disconnect the neutral conductor as well as the lines in a 4 wire distribution system (Poland).

It would be much appreciated if someone could point me in the right direction.

Thanks.

 

[rbulsara]

since no one answered this..i will attempt. I am in the USA. But regargless of where you are the fact is:

1. If this is a simple disconnect for a circuit, the neutral (grounded conductor) should not be interrupted.

2. If you are talking about a transfer switching between a generator and a utility (or any two different sources), it will depend on the way two sources are grounded. In general if both sources are separately grounded, you should switch the neutral in the transfer switch. If the two system are arranged for a single point (common) grounding, only 3 pole will suffice.

 

[alehman]

I think some European codes require the grounded circuit conductor to be switched with the phase conductors. I don't know any specifics.

 

[avishai]

Hi DaveRosser , as you see in the answers you already got the answer is not simple.
In fact it all depends on two things : your electricity provider regulations and your grounding regulations . According to IEC regulations if your system is a TNC-S system or a TNC system ( neutral grounded at the supply point ) you can only use a 4 poles swich if your second supply is grounded also ,this grounding is based on you electricity supplier instructions . Based on IEC standards you can use a 4 pole transfer swich only is you transfer from one supply to an alternative one usually a generator or a ups system , otherwise you should use a 3 poles swich.

A.Rash BScEE & PE
a_rash@bigfoot.com

 

[DaveRosser]

Thank you for your answers.

This is a disconnect for a control panel on an industrial machine, not a generator/transfer switch application..(I should have been more specific). In reality, the neutral will not be used because the loads are either three phase, or 24vdc. I'll have to get more information on the distribution system, as far as TNC, TNC-S, etc. All I have been told at this point is that it is a 3-phase 400vac system with a neutral. I dont really see a point of even bringing the neutral to this machine, as it is not used, but perhaps it is required?