insulation resistance problem

[PAUL M]

we check at 500v d.c. ,and we unplug our tv and everything ellse why we are at it.

 

[EasyFox]

I tend to unplug everything then test at 250v as this at least gives an indication of anything still plugged in thats hidden away. If the reading is ok at 250v I bang 500v round the circuit.

Hidden items I've come across in the past:

fcu + neon behind cookerhood
Floods spured off ring final with fcu's in loft space (blew a pir on security light last week when meggered circuit )
Tv amp in loft (either off the lighting circuit or ring)
Plug in air freshner behind bed
Tube heater in toilet taken off ring to fcu
Fitted appliances in kitchen no isolator above worktop.
Oven plugged into ringfinal.
Spur from ring final out to greenhouse feeding heaters/lights

 

[PAUL M]

each to their own easyfox .

 

[Shakey]

I tend to unplug everything then test at 250v as this at least gives an indication of anything still plugged in thats hidden away. If the reading is ok at 250v I bang 500v round the circuit.

Hidden items I've come across in the past:

fcu + neon behind cookerhood
Floods spured off ring final with fcu's in loft space (blew a pir on security light last week when meggered circuit )
Tv amp in loft (either off the lighting circuit or ring)
Plug in air freshner behind bed
Tube heater in toilet taken off ring to fcu
Fitted appliances in kitchen no isolator above worktop.
Oven plugged into ringfinal.
Spur from ring final out to greenhouse feeding heaters/lights

Easyfox old chap

thats exactly what i teach my students to do,
and 612.3.2 specifically allows you to do it

 

[tc3]

finally a sensible regulation hurrah

 

[mdshunk]

I tend to unplug everything then test at 250v as this at least gives an indication of anything still plugged in thats hidden away. If the reading is ok at 250v I bang 500v round the circuit.

Hidden items I've come across in the past:....

That's what I've taken to doing as well. Since we're dealing with a phase-to-neutral voltage of 120V here in the states, I'll do my preliminary check at 50 or 100 volts; whichever scale the megger I'm using happens to have. The stuff I miss are things like chime transformers, roof exhaust fans in the attic, television amplifiers, plug-in air fresheners, dimmer switches, and switches w/neon lights.

You all might find it interesting that megger checks are not required here in the US at all, at any interval. I do them myself following water damage, fire damage, or a hard lightning strike. Seems like the only prudent way to pass or fail the installed wiring following such occurrances.

 

[EasyFox]

md you ever worked over here in the uk?

 

[mdshunk]

md you ever worked over here in the uk?

No, but I'm pretty well tuned in to the way you all do things there. Pretty much the same as here, except you use a lot of loop feed circuits, and we're not allowed to do that here. You switch pretty much everything, which really helps with your regular testing you do of the wiring, I'm sure. You all are required to do a lot of testing on certain intervals, and we have to do *zero* testing of anything here in the states. Smart electricians do, however. Sort of a "cover your butt" type of thing. I do have a copy of the 17th edition regs, just for my own reading entertainment.

 

[greekislandlover]

I'm sure I can think of many other books I'd rather have for bedtime reading! But it's certainly interesting to know the differences between the two countries.