Insulation resistance test on new circuit

[Lilyrose08]

Iam currently on a new build project and I've been carrying out some IR test prior to everything being boarded up. The construction is all timber frames with celotex ply and plaster board, I have connected up the kitchen ring with connector blocks to carry out IR tests and I have been getting low readings for a new install L/E 50Meg N/E 45Meg and L/N about the same the readings do increase when you hold test button down.
Do u think these low readings could be down to damp and moisture in the air as it is a building site and very cold and exposed.
Im a little bit concerned as I normally expect greater than 50Meg
any ideas anyone would help
thanks

 

[Lilyrose08]

I meant greater than 500 Meg

 

[bluestar]

look in the regs minimum values

 

[i=p/u]

could be moisture or very long ciruits or you testing a lot of ciruits..... but well within limits... sleep tight

 

[Brightspark2]

Yes could be down to moisture and damp...

 

[KevinS]

If its rising when you hold down the test button, I would suspect damp.
i wouldn't worry about the readings you are getting.

 

[topcat]

Well over min for IR test so no problem may be damp and will improve more when in use but still well over min.

 

[Amp David]

Leave the test on for a minute and see what you end up with then.

 

[SPARTYKUS]

look in the regs minimum values

If its a new install the readings should be infinite.

 

[somersetsparks]

should be but I would rest easy with 50meg on new builds, usually damp.

 

[Amp David]

If this is testing pre 2nd fix and cables are joined with connector blocks, then how can damp effect things really?

Ok if sockets have been fitted and screwed back and walls are of backing plaster/skim, I can fully understand damp cuasing an issue in the backs of sockets.

 

[SPARTYKUS]

Lilyrose08

I would be tempted to take the couple of hours on the chin this time & break the ring into two legs, test each, then narrow down which half is providing the low reading & hunt the cause down. When you have found it, and can see it, you will be well chuffed.

Ps lets face it, the damp is a guess!

 

[ezzzekiel]

Chasing a 50M reading lol

 

[AndyL]

If just testing one new circuit I would also expect this to have a reading off the scale, take a bit of time, break the circuit down and find which part is giving the low readings

 

[Amp David]

Chasing a 50M reading lol

Yeah, you are right in what you say, but on a new circuit, i'd what max readings for whatever meter I was using

 

[moddeydhoo]

YOU CAN NOT BE A SPARK SO WHY ARE YOU TESTING, WHAT A LAUGH, THOSE READINGS TO ME AS A SPARK ARE FINE. NEW BUILD 2 MEG OHMS OLD 1.75 IS LEGAL MEG OHM IS VERY LARGE
MΩ one million ohms

 

[SPARTYKUS]

YOU CAN NOT BE A SPARK SO WHY ARE YOU TESTING, WHAT A LAUGH, THOSE READINGS TO ME AS A SPARK ARE FINE. NEW BUILD 2 MEG OHMS OLD 1.75 IS LEGAL MEG OHM IS VERY LARGE
MΩ one million ohms

Cetainly is large.

Not large enough for me though

If you were working for me, and presented an EIC with the new circuit readings as 2M Ohms, you'd be going back and finding out why.

But each to their own !

 

[Guest55]

on newly installed wiring 2 meg is certainly not acceptable.
but 50 meg on newly plastered walls is pretty good and will certainly climb after a drying period.
liking the new avatar sparty.

 

[moddeydhoo]

Read the reds 2meg is 2000000 ohms

 

[moddeydhoo]

Regs actualy says 1meg but that is individual circuit 612.3.2 table 61