Slow insulation resistance?

[whazza22]

Carried out an insulation resistance test on two lighting circuits today and both circuits the reading was very slow.

It started about 200Mohms and gradually goes up in tens, and stops on 400Mohms

Normally the meter shoots straight to >1000

Any ideas?

 

[telectrix]

at 200 meg, its well above requirement . are you sure all lamps are out?

 

[IQ Electrical]

Carried out an insulation resistance test on two lighting circuits today and both circuits the reading was very slow.

It started about 200Mohms and gradually goes up in tens, and stops on 400Mohms

Normally the meter shoots straight to >1000

Any ideas?

That can be a sign of dampness but as Telectrix says, you're miles in at 200 to 400 Million Ohms!

 

[telectrix]

sure you not got hold of the leads with sweaty hands?

 

[whazza22]

All lamps were defo removed and I disconnect the ballast from fluroscent fitting.

Cables were in connector blocks when testing.

 

[sparx24]

Assuming meter batteries are ok it appears to be something capacitive charging up, not pyro/FP type cable by any chance? since these can charge.
[Capacitor = two conductive surfaces with insulator between, just like above cable types].