Proving units maximum voltage

[Ziggie]

I decided,having lived with using a live circuit, to buy a proving unit. I opted for a Kewtech Prove 4 which covers 5 voltages between 690volts and 50 volts. The device starts at 690 volts which is ok for my Megger 2 pole tester. My fluke clamp meter has a limit of 600 volts. The second problem is that the unit spends only seconds in the low voltage ranges and it’s too fast to check the readings easily in these ranges.

Has anyone used this device with testers that have lower limits than the 690 volts ?

 

[newfutile]

A proving unit is not really to check the voltage readings , just to prove your approved voltage tester is working both before and after testing the isolated (and locked off) device.

you have to test at or above the voltage you expect to find on the device under power.

 

[DPG]

I think what he means is that the kewtech unit outputs 690V initially, which is above the maximum limit of his Megger voltage tester.

The Kewtech one starts off at 690V and if you hold the probes in it will step the voltage down every second or two. This is to do a full test of the kewtech voltage probe, so that you can confirm each voltage range is working OK

 

[nicebutdim]

Fluke PRV240 puts out 240V AC/DC. Martindale PD440 will give 440V AC. Neither offers a range of voltages.

 

[pc1966]

All voltage testers are safe to much higher than the "rated" voltage. Going 10-20% over spec is not a problem and anything for power system use in the UK should be CAT-III or CAT-IV anyway:

Measurement category - Wikipedia

en.wikipedia.org

 

[nicebutdim]

I have a socket and see unit that turned up cheaply somewhere. It lights up and squeals when stabbed with probes, which is more than adequate for my basic requirements.

 

[Ziggie]

My fluke clamp meter says don’t use if voltages greater than 600volts - and the kewtech starts at 690 volts and you can’t say “please start lower than 690 volts.

 

[Ziggie]

If the proving unit had started at the low end (50volts) and slowly rise to the higher voltages where you could halt before going to higher voltages by removing the probes surely would have been safer ?

 

[brianmoooore]

I suspect the 600 volt limit is the max. rating of the leads Cat iv GS38 thing.

 

[DPG]

I think suitable devices have been given in post 4 by nicebutdim.