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marcros

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@petermillard

this has just flashed up on my suggestions to watch. What is the kit that you are using at 1:26, it looks like exactly what I need but I dont know what to search for!

 
In most cases those non contact testers are nothing more then a toy, use a proper tester your life can depend on it.
 
Non Contact Voltage Tester. Screwfix ones are twice the price of Toolstation.
 
You should never, ever rely on a non-contact voltage indicator for proving dead.
They are an indicator ONLY, and generally restricted to identification of wiring being live, or in hazardous situations where a readl 2 pole voltage indicator cannot be safely used.
For proving dead, a two pole voltage indicator is needed, which also needs to be proved before and after use on a known source.
Please don’t take risks with electricity, 10mA across the heart is enough to kill a healthy adult.
 
Which 'proper tester' do you recommend?
Go to any trusted electrical supplier (tools included) and ask for a digital multi-meter.
Get what you can afford. Prices £20 upwards
Can tell you (accurately) if mains present.
If wire A connected to wire B
If a circuit is electrically neutral, i.e. you can handle it. Google for more info

For a quick "is it live" check, the non-contact are fine.
checking twice is usually quicker than a trip in an ambulance with smoke from your hair.
 
Fortunately I didn't learn the hard way, otherwiese I might not be here to write this.

I am 'old school' and was an electronics engineer all my working life so should have realised what was happening. I'd been fitting a replacement CH boiler and was puzzled why the permanent live to the boiler was showing up OK indoors but not on the machine itself. "Old School' still use the neon screwdriver - yes, yes, but they work ! But not if standiing on wooden steps with rubber soled shoes on, and that is why they are not favoured.

The DVM is the answer I agree and I have several, but in a working situation often require 3 hands, hence the atttraction of alternative indicators.
Rob
 
I have the Fluke voltstick, but find I don’t use it much. It’s handy for a quick survey of the fault, as it can indicate voltage without the need to open junction boxes, sockets, etc. It’s ok for suggesting live, but not for proving dead.

It gives false positives, eg where a dead wire runs alongside a live wire (ghost voltage), and also claims my iPad casing is ‘live’ when charging. This is due to capacitive coupling through the power supply and is harmless.

It gives false negatives, eg in screened or armoured cable.

The two-prod indicator and proving unit is ideal - it doesn’t require current through the operator, and there are no batteries to run out or settings to get wrong. A bit expensive for the home gamer replacing the odd cracked socket.



Good habits are a great strings for your safety bow:
- Don’t rest one hand on things while working with the other.
- Stop twiddling screwdrivers by the metal shaft. Preferably, use VDE insulated tools.
- Develop the skill of making off connections without ever touching conductive bits - use pliers to double over the conductors, for example.
- Wear rubber-soled boots. If anyone tries to insist you take off your boots in the house, use the boots to kick them squarely up the backside.
 
Last edited:
Good habits are a great strings for your safety bow:
- Don’t rest one hand on things while working with the other.
- Stop twiddling screwdrivers by the metal shaft. Preferably, use VDE insulated tools.
- Develop the skill of making off connections without ever touching conductive bits - use pliers to double over the conductors, for example.
- Wear rubber-soled boots. If anyone tries to insist you take off your boots in the house, use the boots to kick them squarely up the backside.

Excellent advice here and something I try to follow. I always use VDE tools when working on electrics. I do though make heavy use of my non contact tester and find it a very useful bit of kit but it is not a replacement for my multimeter which does get used when needed as well.
 
I've posted this before but worth repeating. Pre-Part P refurbishing a flat in London. Old school wiring, singles inside metal conduit. Replacing the consumer unit. Out to the upriser cupboard in the common parts landing and remove the fuse feeding the flat and take it with me. Lock the upriser cupboard door. Double-check no live - confirmed. Remove all wires from the old consumer unit and start to rewire in the new one.

My knuckle touched one of the neutrals and I got a belt. Tested the neutral and it was live. So....your starter question for 10...how did that happen ?
 
I'm gonna go for either a reverse polarity connection or a live making contact with a neutral via a sharp bit in a conduit.

My dad was a sparky from when he was 16 til a couple of years ago when he retired, and living in a small valley and a member of the rugby club there would often be phone calls requesting a quick hand with a problem. One evening he had a call from a mate who was getting a buzz from the kitchen sink. My dad went there and EVERYTHING metal tested as live. Pipes, sinks, radiators and even the gate outside had a bit of live in it. It transpires that the neighbour next door had been nailing some boards down and had sunk a nail between a live and earth. Normally that would trigger a fauly, but an old voltage trip couples with the houses being up on a rocky hill with dodgy earth spike connections meant there was a ring of live earth around the house which was feeding back up into next door via they're earth spike! In the back of his van he had a tester for his tester to verify it was working before starting a job.the lat 20 years or so he was a fitter working with 11kv plus, any bad habits you may pick up as a normal sparky, would soon kill you at those voltages!
 
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