On Tue, 17 Nov 2009 19:34:15 -0800 (PST)
NT wrote:

On Nov 17, 9:09Â*pm, John Rumm wrote:
NT wrote:
On Nov 17, 5:07 pm, "Peter Andrews"
wrote:
I've decided that I should add a resistance tester (generically known as a
Megger) to my toolbox and have been surprised at how few there seem to be
available - given that every electrician should(?) have one for testing.

TLC have one for about £80 - can anybody recommend this or another one for
occasional use (2 - 3 times a year)!

Peter

If you dont need to use it to fill any forms, you can make your own in
minutes for a few quid.

Got a circuit for that?


The overview is that you use a high voltage source, rectify and more
or less smooth it, through a resistor to limit current to a non-lethal
amount, then feed it through a current meter (multimeter) and the
insulation under test. A second meter monitors the test voltage,
though this could be omitted for approximate tests.
snip

N

Alternatively, you could do what I did, look on ebay for an old wind-up
megger in a nice leather case complete with probes for about £10.
Works a treat as long as there are no Prat-forms to be filled in. I
can tell if it's under 0.1 ohms, or over 10 meg, but not exactly what
it is, but then who cares (apart from Tony Prat-Prescot).

R.