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Topic Title: Bonding requirments for fixed machine panels
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Created On: 18 September 2013 04:07 PM
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 18 September 2013 04:07 PM
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adamcollier

Posts: 1
Joined: 25 July 2008

Ok, I am involved in producing electrical test scripts for large pieces of fixed automation equipment. The equipment chassis, trunking, motors etc are all bonded in accordance with BS EN 60204-1, however there are a lot of fixed panels that are no bonded.

My question and interpretation of 60204-1 is that if there is no electrical equipment attached to the panels in question and there are no cables at mains voltage that can come into contact with these panels from behind is bonding necessary? after all these panels are attached to the main chassis which itself is bonded.

60204-1 states that: -

'8.2.5 Parts that need not be connected to the protective bonding circuit
It is not necessary to connect exposed conductive parts to the protective bonding circuit
where those parts are mounted so that they do not constitute a hazard because:
- they cannot be touched on large surfaces or grasped with the hand and they are small in
size (less than approximately 50 mm × 50 mm); or
- they are located so that either contact with live parts, or an insulation failure, is unlikely.

In this case the panels in question, they are located such that their contact with live parts or an insulation failure is unlikely point two above. So bonding is not needed??? any views welcome
 20 September 2013 03:08 PM
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iie63674

Posts: 80
Joined: 17 May 2006

8.2.1 of 60204-1 states that:
The protective bonding circuit consists of:
- PE terminal(s) (see 5.2);
- the protective conductors in the equipment of the machine including sliding contacts
where they are part of the circuit;
- the exposed conductive parts and conductive structural parts of the electrical equipment;
- those extraneous conductive parts which form the structure of the machine.

The last bullet point seems to answer your question.
 20 September 2013 11:10 PM
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gkenyon

Posts: 4488
Joined: 06 May 2002

Originally posted by: iie63674

8.2.1 of 60204-1 states that:

The protective bonding circuit consists of:

- PE terminal(s) (see 5.2);

- the protective conductors in the equipment of the machine including sliding contacts

where they are part of the circuit;

- the exposed conductive parts and conductive structural parts of the electrical equipment;

- those extraneous conductive parts which form the structure of the machine.


The last bullet point seems to answer your question.
Is a "panel" an "extraneous conductive part", given the definition in EN60204-1 which is as follows:

conductive part not forming part of the electrical installation and liable to introduce a potential, generally the earth potential


(which is very similar if not the same to BS7671)?

I'm not sure a panel on the machine can, under general circumstances, introduce a potential from outside the machine (or even the installation) ?

Of course, that doesn't mean the panel shouldn't be bonded for EMC purposes!

-------------------------
Eur Ing Graham Kenyon CEng MIET TechIOSH
 23 September 2013 10:38 AM
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iie63674

Posts: 80
Joined: 17 May 2006

Graham, I'd have thought these panels are as likely to introduce the earth potential as any other conductive part of the machine.
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