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neon indicators

Postby remelad » Tue Feb 07, 2012 7:54 pm

Hi All,
can someone answer a simple question, when doing insulation resistance its a requriement to remove the neon light from the circuit. I always use terminal blocks as a lot of neon lamps are not removable, is there another way to test without all this hassel and time consumption.
Many thanks in advance Remelad.
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Simply Build It

Postby ericmark » Wed Feb 08, 2012 8:27 pm

Using the 250 volt range will not harm the neon as it is it's run voltage but of course the reading will be low because of the neon. However in real terms one can allow for this and it does give a reading good enough to show if there is another fault one would have to note on the paperwork low reading due to neon.

The earth reading will not be effected as the neon will be line to neutral not line to earth.

Also normally the neon is on output of a FCU not input so normally not a problem.

One must use common sense. The old BS7672:2008, not got new copy, states how we must use an RCD when buried less than 50mm anyone with a little sense will realise this does not apply to SELV supplies like to the door bell. Although it does not say that.

So one has to consider the testing is non destructive so we would not cut a wire to test. It is very unusual to find a neon that can't be removed but neons and filters are a problem where there is no as built plans and it is so easy to kill filters during testing. So where uncertain it may be a good idea to use the 250 volt range.
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Postby remelad » Mon Feb 20, 2012 8:14 pm

Hi erickmark,
thanxs for the advise sorry for not replying sooner been away.
What I will do is test both ways,
Kind regards remelad
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