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IEC - armour as grounding conductor?

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ctpt

Electrical
Mar 9, 2004
29
Hi everybody,

My questions are for experts in the IEC world. I understand that as per NEC, a separate grounding conductor is run with phase conductors (as a fourth core in a three phase cable or as a separate grounding conductor) especially for grounded systems <1000V. Please correct me if I am wrong. Now, my questions are –

1. Is there any such requirement in IEC? I understand that in IEC there is no such mandatory requirement of running a fourth conductor for grounding alongside the phase conductor. I also understand that if we are using an armoured cable, IEC allows the armour to be used as a grounding conductor(PE).

2. If armour can be used as a grounding conductor, is there any IEC which tells us what should be minimum cross section of the armour and/or does it tell that armour should withstand the full ground fault current for that particular duration. If both the cases I would like to know the relevant IEC code numbers.

(I was referring to some standard cable manufacturer’s data and found that the standard armour cross section in some cases may not be able to carry the full fault current, particularly in a 400V solidly grounded system with high fault current)

You help will be much appreciated.

Thanks,
 
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SUGGESTION:

Post your question in the "IEC (electrical) Code Issues" Forum # 249.
 
You will need to check if the Wiring Regulations in the appropiate country.

"IEC 60364 Electrical installations of buildings" purpose is to provide guidance only. Each country is responsible for publishing its own wiring regulations. This is because the different wiring regulations within Europe and indeed worldwide were two diverse to harmonise into a single standard.

e.g.
UK: BS7671, Requirements for Electrical Installations
Ireland: ET101 National Rules for Electrical Installations

In Ireland (ET101) armour may be used as a protective conductor provided it is equivalent to the minimium calculated cross sectional area of copper. The exception to this is in hazardous areas where a seperate earth conductor is required in all cases.


 
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