by ericmark »
Thu Dec 24, 2020 11:55 am
There is a difference between nominal voltage and actual voltage, I think our peak voltage is around 325 volt for a 230 volt AC system, and most equipment is designed to take 500 volt which is the voltage we use to test the insulation on our 230 volt supplies.
As a boy I remember the signs danger 250 volt or 440 volt, I don't remember 440 volt, it was 415 when I started, and today it is 400 volt.
Yes at the incomer it can be 216.2 to 253 i.e. 230 volt -6%/+10% so really 234 volt +/- 8% so a tester with a nominal voltage of 230 volt should work 216.2 to 253.
As to what the proving unit produces most state 240 volt, and the testers I have seen may say 230 volt but the spec says "CAT IV 600 V, Cat III 690 V safety rating Fluke’s family of Two-Pole Voltage testers comply with both regulation HSE GS 38 (tip caps) and IEC EN 61243-3: 2010." what do you think 600 V means?
I have questioned the use of battery less voltage testers and proving units, the tester should have no battery or switch, so can't in error be switched off, and the tester is tested, then the item is tested then the tester is tested again.
But the proving unit I had produced 250 volt, my question was why, I want to know if the tester will detect any voltage which would be dangerous, so if over 50 volt AC I want to know, so lighting all neons or LED's from 6 to 400 volt is no good if at 50 volt non light.
So Kewtech Kewprove 3 Proving Unit say Output voltage: 180V into 6.8KΩ, 720V - 820V into 10MΩ so one would hope a Kewtech voltage tester can take 820 volt?
So all voltage testers will have a proving unit which is designed to be used with it, so look at the spec of the proving unit, and then you will know what voltage the tester can stand.
Put your self in the position of the person on the phone at the manufacturers help line, do you really think you are talking to the designer, if the spec says 230 volt they are reading the spec same as you.
So clearly you should not be using a 400 volt tester in a mine or quarry with a 550 volt supply, but other than mines or quarries not seen supply other than 400 volt for years.