Proving Isolation

Piratepete · Jul 21, 2012

Hi Guys My Martindale VI 13700G Voltage Indicator has gone walkies. For proving isolation do I have to have a single function voltage tester like the Martindale or could I use a multifunction instrument like the Fluke T5-1000 Electrical Tester (which I want for it's AC current open jaw measuring)? Also - do I have to have a proving unit? Cheers Pete

telectrix · Jul 21, 2012

you can use the t5-1000, and for a proving unit, i use the supply i'm working on ( incoming terminals on main switch )

snowhead · Jul 21, 2012

There's been a thread on this recently.

A true proving tester shouldn't have batteries, like a Multi or clamp meter.

Personaly I've never had a problem with relying on a battery powered meter using test live, test dead, test live again to prove meter.

Guest123 · Jul 21, 2012

Technically, you would need an approved voltage indicating device to confirm isolation.

Have a read here.....

http://www.electriciansforums.net/electrical-tools-products/54942-voltage-indicators-gs38.html

Piratepete · Jul 21, 2012

Hi Guys
You've just forced me to read my copy of GS38 (Feb 1995). Unless it's been revised, clause 17 states that 'a proprietary test lamp or 2-pole voltage detector' is 'preferred' to a multimeter - not obligatory. Also 'a known live source of similar voltage to the circuit under test' may be used for proving. But clause 12 says that 'Instruments used solely for detecting voltage' should have non detachable leads and max 4mm bare probes. Anything else is (not recommended) but is allowed. It's all a bit ambiguous!
I could buy the Fluke T50 as well for a mere £22, it has a captive lead but it hasn't got 4mm probes.

sparks1973 · Jul 21, 2012

Piratepete said:
Hi Guys My Martindale VI 13700G Voltage Indicator has gone walkies. For proving isolation do I have to have a single function voltage tester like the Martindale or could I use a multifunction instrument like the Fluke T5-1000 Electrical Tester (which I want for it's AC current open jaw measuring)? Also - do I have to have a proving unit? Cheers Pete

the T5-600 and the T5-1000 are NOT TO GS38.....an approved voltage indicator (such as a martindale) or the fluke T50-T140 are suitable for doing a safe isolation....together with a KNOWN SOURCE OF SUPPLY....such as a proving unit or the incoming side of a DP/TPN iso....

sparks1973 · Jul 21, 2012

i use a GS38 DI-LOG myself.... its better to have the right equipment to carry out such an important task as a safe isolation rather than just risking it by using unsuitable equipment.....

telectrix · Jul 21, 2012

well here we are then. noin-detachable leads and no other functions

Piratepete · Jul 21, 2012

sparks1973 said:
the T5-600 and the T5-1000 are NOT TO GS38.....an approved voltage indicator (such as a martindale) or the fluke T50-T140 are suitable for doing a safe isolation....together with a KNOWN SOURCE OF SUPPLY....such as a proving unit or the incoming side of a DP/TPN iso....

Why do these comply? They're multifunction and require batteries. I note that the T50 will read volts without batteries - not sure about the T100 range.

Pete

sparks1973 · Jul 21, 2012

the T50-T140 will read voltages throughout the instruments range WITHOUT battery/s....the battery/s are there for the continuity function (belling out)....

sparks1973 · Jul 21, 2012

telectrix said:
well here we are then. noin-detachable leads and no other functions

yep Tel....pure genius these arn`t they...lol.....

Piratepete · Jul 21, 2012

sparks1973 said:
i use a GS38 DI-LOG myself.... its better to have the right equipment to carry out such an important task as a safe isolation rather than just risking it by using unsuitable equipment.....

I do agree with you - sigh. Just think the Martindale is expensive for what it does. Also trying to keep the number of test instruments I carry around to a minimum! So anything multifunction is useful - if safe in their application.

sparks1973 · Jul 21, 2012

Piratepete said:
I do agree with you - sigh. Just think the Martindale is expensive for what it does. Also trying to keep the number of test instruments I carry around to a minimum! So anything multifunction is useful - if safe in their application.

well the reason why martindales are specifically mentioned by some firms is they will detect ghost voltages that some other voltage indicators wont pick up.....quite a few times now i have seen folk just waving a neon vaguely over exposed conductive parts and thinking thats safe isolation......crackers really....