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Discuss 537.2.1.3 in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

B

bahco

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just been having a debate with my mate regarding the regulation below

537.2.1.3

" where a installation or a item of equipment or enclosure contains live parts connected to more than one supply, a durable warning notice shall be placed in such a position that any person before gaining access to live parts, will be warned of the need to isolate those parts from the various supplies unless a interlocking arrangement is provided to ensure that all the circuits concerned are isolated"

so the way he interpreates it is that say at the bottom of the stairs you have a 2 gang switch, up lights down lights, then in the mains board up and down lighting circuits.

in that switch there are 2 circuits so you isolate the down lights open up the switch the up lights side of the switch is still live.

now i can see where he is coming from but in the above reg it says " connected to more than one supply "

now i would say that the 2 circuits in question are on the same supply, just different circuits.

anyway your views please lads

:rolleyes:
 
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S

Spudnik

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  • #2
I think you will find that this mainly relates to DB's and enclosures with various supplies and circuits in them.

A switch doesnt really have live parts, only terminals which you should only be able to access with an insulated screwdriver.

Shouldnt really be too much of a worry as you should always 'prove dead' especially if there is doubt.

Thats my take on it.
 
B

bahco

  • Thread Starter Thread Starter
  • #3
yeah i agree with what your saying jason as that is my take on it, however my mate is currently doing his 17th edition and his tutor used the 2gang switch as a example to the class.

there was quite a bit of debate about it so he says
 
N

ninjadeathstalk

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  • #4
537.2.1.3

" where a installation or a item of equipment or enclosure contains live parts connected to more than one supply, a durable warning notice shall be placed in such a position that any person before gaining access to live parts, will be warned of the need to isolate those parts from the various supplies unless a interlocking arrangement is provided to ensure that all the circuits concerned are isolated"
I think this reg is to do with dual supply circuits, where you have a primary supply and a secondary supply in case of failure of the primary supply.

As you can see it does say that there are more than one supply to the relevant piece of equipment, not to another piece of equipment.

So it would need to be isolated from all supplies or the equipment will still be live if only one supply was isolated. Therefore it would need a warning label to say that this was so.

From the end of the statement it would not need a warning if an interlocking arrangement is provided, ie. if all supplies can be switched simultaneously then no warning is needed.
 
G

Guest123

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  • #5
Back up geneys and UPS spring to mind.

I only think of it because of test forms, "adequate arrangements for alternative sources" or something like that.
 
N

ninjadeathstalk

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  • #6
My thoughts as well lennytheloon.

Back-up generators, etc. like those in a hospital.
 
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