Virtual wiring practice

[mjtefc9]

If you think you wont make a mistake, that is your first big mistake. Being an electrician means that without a doubt at some point you will experience an electric shock. Safe isolation is just part of the strategy to staying alive. We wear thick rubber soled boots and use fibre glass ladders to increase resistance to a point that if or should I say when we get a shock it is sufficiently high to mitigate the fatal aspect of that shock. We never come in out of the rain and start on electrics 'til we are dried out. Working on a rig at 230v imho is an invitation to get a shock. Your strategy then would be to use a xformer to limit the voltage to 55v (it is centre tapped!) in the event of a shock. If you are not thinking like this (being OCD safe!) you would not be working with me for a start, you must take safety very seriously. Further you may well be working on your own if you do come to grief (God forbid) there will be no one there to assist or remove you with a large lump of wood by hitting you with it, so safety first I would say, but that may be a bit over the top for some. For me, I aint taking no chances neither should you. Oh and if you do need help with a large lump of wood in case of shock, happy to help

OH I will be stupidly OCD regards the safety.. I will only energise for a minute and turn off and unplug.. it is purely to check my wiring is correct and practice testing..

My wife would love to whack me with a lump of wood though !

 

[Vortigern]

I will only energise for a minute (to) check my wiring is correct

No, you have that the wrong way around. You don't switch on to check you wiring is correct. It must be off to check it is correct and tested prior to commissioning. Oh dear, that method is known as the big bang test.

 

[mjtefc9]

No, you have that the wrong way around. You don't switch on to check you wiring is correct. It must be off to check it is correct and tested prior to commissioning. Oh dear, that method is known as the big bang test.

That is what I meant! Sorry..

 

[Vortigern]

Just tell the wife if the lights dim for a while suddenly, come to the garage with a big piece of wood to hit me with.

 

[mjtefc9]

Will this be okay to carry out my dead testing in sequence? I don't want to spend over £100 on a tester yet..

https://www.rexel.co.uk/uki/c/Digital-Multimeter/p/1052043549

 

[DPG]

Will this be okay to carry out my dead testing in sequence? I don't want to spend over £100 on a tester yet..

https://www.rexel.co.uk/uki/c/Digital-Multimeter/p/1052043549

No, you need an approved voltage Tester and ideally a proving unit.

Become familiar with the proper method for testing for dead. This is crucial.

 

[mjtefc9]

No, you need an approved voltage Tester and ideally a proving unit.

Become familiar with the proper method for testing for dead. This is crucial.

Any suggestions on a reasonable unit ?

 

[DPG]

Any suggestions on a reasonable unit ?

Kewtech are generally good value I believe.

 

[mjtefc9]

Kewtech are generally good value I believe.

Thank you

 

[mjtefc9]

Thanks for everyones help here !

Just need to chose the right meter for dead testing and I'll leave you all alone !

This one okay ?

 

[Vortigern]

Personally I think they are crap. Very poor construction and gives false positives. Have watched a couple of trainees with those and see them looking puzzled when all the lights go red and it bleeps even when the circuit is dead. I am sure there is some very good technical explanation as to why it does that but when you are dead testing you dont want the unexpected. Fluke two pole voltage tester T90 at least I would say.

 

[mjtefc9]

Personally I think they are crap. Very poor construction and gives false positives. Have watched a couple of trainees with those and see them looking puzzled when all the lights go read and it bleeps even when the circuit is dead. I am sure there is some very good technical explanation as to why it does that but when you are dead testing you dont want the unexpected. Fluke two pole voltage tester T90 at least I would say.

Thank you yet again !

 

[DPG]

Personally I think they are crap. Very poor construction and gives false positives. Have watched a couple of trainees with those and see them looking puzzled when all the lights go red and it bleeps even when the circuit is dead. I am sure there is some very good technical explanation as to why it does that but when you are dead testing you dont want the unexpected. Fluke two pole voltage tester T90 at least I would say.

That's probably when they've 'woken it up' by touching the probes together. This puts it in resistance check mode.

 

[Vortigern]

touching the probes togethe

No it is only when they are testing cable directly L-N and the circuit is isolated. No touching of probes involved and it momentarily shows voltage and beeps.

 

[DPG]

No it is only when they are testing cable directly L-N and the circuit is isolated. No touching of probes involved and it momentarily shows voltage and beeps.

Mmm, not sure then. Ours don't do that.

 

[Vortigern]

Yep happened with two different trainees and different Kewtech voltage testers numerous times, the same one as linked by OP

 

[mjtefc9]

Sorry for the stupid question.. but In college we used the expensive Megger multimeters and we obviously get readings whilst dead testing.

With these meters, I take it you either correct or incorrect no specific reading ?

 

[Lucien Nunes]

Don't use a yellow site transformer to feed a mock-up test board of domestic wiring!

The transformer output is centre-tapped to earth, i.e. both the circuit conductors are lines and there is no neutral. If you are rigging up normal domestic wiring the switches, MCBs etc are single-pole and therefore not suitable. All switchgear downstream of a CT-E transformer must be double-pole, and any live testing you do will be completely out of whack.

 

[mjtefc9]

Don't use a yellow site transformer to feed a mock-up test board of domestic wiring!

The transformer output is centre-tapped to earth, i.e. both the circuit conductors are lines and there is no neutral. If you are rigging up normal domestic wiring the switches, MCBs etc are single-pole and therefore not suitable. All switchgear downstream of a CT-E transformer must be double-pole, and any live testing you do will be completely out of whack.

It's okay.. I'm scrapping that idea. Going to concentrate on wiring and testing whilst not energised till I'm more confident.

 

[Lucien Nunes]

Energising is really the very last stage anyway and even the dead tests should be something of a formality. If you are practising craft skills of intstallation work, most errors you commit will be evident to the naked eye and by feel. If work is carried out correctly and looks and feels right, it will almost certainly test fine. OTOH, testing will not necessarily reveal poor quality work; only work that is so bad it doesn't even function from the get-go.

When your work is demonstrably sound and consistent, and your dead test results dependable, then it will be quite safe to energise your board with real mains.