Do neon indicators affect Zs test results?

[joe.ninety]

I know that having a neon in the circuit screws up IR testing, but I just wondered if the same applies to Zs testing.

Many thanks

 

[Ian1981]

Zs is the total earth fault loop so I wouldn't have thought so as neons on the load side connect across live - neutral.

 

[joe.ninety]

But aren't non-trip Zs tests done using 3 leads?

 

[Taylortwocities]

It doesn't matter. The non-trip thingy is just to trick the RCD into not tripping.

 

[Wilko]

And resistance wise, I think the neons are 200k Ohms (ish), so even if they were in the circuit, they're not going to make an impact on a measurement that's 1 Ohm

 

[Deleted member 9648]

I know that having a neon in the circuit screws up IR testing, but I just wondered if the same applies to Zs testing.

Many thanks

Whenever there's a low IR thread on here someone always pipes up 'is there a neon?'. But bear in mind it would only affect a L-N test, as would any other load connected. A neon will make no difference at all to IR tests to earth.

 

[joe.ninety]

And resistance wise, I think the neons are 200k Ohms (ish), so even if they were in the circuit, they're not going to make an impact on a measurement that's 1 Ohm

I'm sorry Wilko, maybe I'm just being dense, which is more than likely but how would a resistance of 200k ohms not have an impact?

Cheers

 

[The Ghost]

Pop yer glasses on Joe we are gonna zap you with the brain of @Pete999 then all will be seen....Ready?

 

[Wilko]

I'm sorry Wilko, maybe I'm just being dense, which is more than likely but how would a resistance of 200k ohms not have an impact?

Cheers

Hi Joe - just imagining the earth fault loop impedance is expected to be about an Ohm (or so) and if somehow a neon was wired in error from L to E, then its 1 Ohm in parallel with 200,000 Ohms, which is 1 Ohm

 

[telectrix]

Hi Joe - just imagining the earth fault loop impedance is expected to be about an Ohm (or so) and if somehow a neon was wired in error from L to E, then its 1 Ohm in parallel with 200,000 Ohms, which is 1 Ohm

your maths has had me flabbergasted and on 2nd thoughts my flabber has been gasted again. the answer is actually 0.999995 ohms. get it right.

 

[joe.ninety]

Hi Joe - just imagining the earth fault loop impedance is expected to be about an Ohm (or so) and if somehow a neon was wired in error from L to E, then its 1 Ohm in parallel with 200,000 Ohms, which is 1 Ohm

Cheers, I was of course forgetting that the neon is in parallel not series. Time to go to Specsavers, my special glasses are obviously playing up

 

[FatAlan]

Where's Brains Burns when you need him?