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Transformer Secondary

Transformer Secondary

Transformer Secondary

A normal practice of a client of ours is to ground one side of the control circuit transformer secondary creating a common neutral for all the components. One of the components is a programming port that has an outlet to plug their laptop into to power them (120VAC in USA/220VAC in Poland).

We are doing a project for them that is going to Poland and have to have CE mark for acceptance. We have employed a third party reviewer to help us through the process. He has rejected the above circuit citing it is in violation of 60204-1 section 5.1.

Our feeling is this section only relates to the incoming supply conductors only and section 8.3.2 allows for the disputed circuit.

Who is right? Has anyone else ran into this issue?

David Baird
Sr Controls Engineer

EET degree.

Journeyman Electrician.

RE: Transformer Secondary

Since this was posted several months ago, I assume that the issue has been taken care of. But, I'd like to add my thoughts.

Section 5 of the EN 60204-1 is dealing with the neutral of the incoming supply conductors (if present). Not locally created power. If a neutral wire comes from the supply conductors, then of course you wouldn't ground the neutral. Just like you don't ground the neutral of your local transformers anywhere other then at the point of the transformer.

You wouldn't ground your neutral in a remote cabinet. Therefore you wouldn't ground someone else's supply power neutral in your cabinet.

RE: Transformer Secondary


Thanks for your response and I agree with you that Section 5 is dealing with incoming power. But what is being flagged as a non-conformity is the grounding of the secondary of our control transformer. Our client and I both have done this many times and is quite the normal practice here in the USA.
The "problem" has been taken care of only because our customer gracefully agreed to allow us to remove this ground to avoid any further conflict.

David Baird
Sr Controls Engineer

EET degree.

Journeyman Electrician.

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