Insulation Resistance - Live to Neutral short

[Newbie90]

Hi all,

Just a quickie. I carried out an insulation resistance test on a lighting circuit which only has two rooms consisting of 4 lights.

Live to earth and neutral to earth was fine but when I tested live to neutral I got a short circuit.

All the bulbs were removed so just wondering if anyone had any ideas?

The Zs reading was 0.73 ohms.

Thanks

 

[Plonker 3]

Insulation of cable had deteriorated?

 

[Bobster]

Not got switches with a neon in them? Is this domestic?

 

[Jay Sparks]

Smoke detectors wired from lighting circuit??? Another load connected somewhere, maybe in loft???

 

[KAS1]

Could be a fault !!!!!!!!!

 

[Plonker 3]

Could be a fault !!!!!!!!!

No that never happens, must be something else causing it too happen.

 

[KAS1]

needs investigating

 

[KAS1]

Method statement to fault find. No 1 put safe isolation in place

 

[Marvo]

If this was an existing circuit and it wasn't tripping or blowing fuses before you arrived then there's some kind of load still connected to it. Check the L-N resistance with a normal multimeter and try figure out what is connected and where.

 

[Deleted member 9648]

Hi all,

Just a quickie. I carried out an insulation resistance test on a lighting circuit which only has two rooms consisting of 4 lights.

Live to earth and neutral to earth was fine but when I tested live to neutral I got a short circuit.

All the bulbs were removed so just wondering if anyone had any ideas?

The Zs reading was 0.73 ohms.

Thanks

Two possibilities-:

1.Something still connected which may or may not now be fried....(tv booster in loft....loft light)?
2. A fault.

 

[Newbie90]

There are no neons on the switches.

There is a tv amp in the attic, would that be spurred from lighting by any chance?

 

[trev]

Crikey.

 

[Newbie90]

Two possibilities-:

1.Something still connected which may or may not now be fried....(tv booster in loft....loft light)?
2. A fault.

Just replied at same time, I'm thinking tv booster

 

[Deleted member 9648]

Two possibilities-:

1.Something still connected which may or may not now be fried....(tv booster in loft....loft light)?
2. A fault.

There are no neons on the switches.

There is a tv amp in the attic, would that be spurred from lighting by any chance?

Yep.....possibly.Hopefully it's survived 500v up it's essentials.

 

[Plonker 3]

There are no neons on the switches.

There is a tv amp in the attic, would that be spurred from lighting by any chance?

did you not think to test to see if that was connected to the circuit?