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I have a question regarding electrical testing please. I have a transformer charger that the spade connections have come out on the transformer power supply end. The plug is a european two pin that is sealed so I cannot see the wiring at the plug end. At the charger end I have a spade connection marked L and the other is of course the neutral / return. I am obviously not an electrician and would like to know if there is no colour coding on the cables how can i test to see which of the feed wires should be plugged into the live ??

Secondly, on three phase wiring with only an earth and not a neutral, how do you test for voltage?? Is it possible to put the voltmeter probes in to any two of the phases and get a reading? That makes sense to me, but I have not done it before so am a little nervous. I currently work on a yacht that has three phase generators and shore power and have much to learn quickly!!

And finally, can anyone recommend a good electrical testing and training school around the hampshire area.

Kind regards,



Electrician's Arms
St Neots
Do you have suitable test equipment rated for the voltages you're dealing with? Single phase voltage is bad enough but three phase can be very nasty indeed.

As for training schools, Steve Willis have a branch in Portsmouth: Contact & Location ? Steve Willis Training Centres


Regular EF Member
Are the two pins different sizes? From what you describe I'm not sure it's UK compliant Riva.
If you don't know what you're doing you need to not be poking around inside that 3 phase generator. You could try googling training schools in your area but most of the quick courses (from what I can make out) don't teach the students anything on the 3 phase side of things.
Sorry if I come across as negative or peeing on your fireworks mate but better safe than dead


Regular EF Member
If it is jut a charger transformer, what is the seconray voltage? I am a bit confused with this. It shouldn't have L and N on the output side.


Electrician's Arms
A plug and three phase in the first post ? perhaps a CU change also would make a hat trick. Really.........


Electrician's Arms
One the first issue i dont understand the set up, so cannot help. If you explain again or have some photos that may help.

Second issue, yes between phases will give you lots of volts and of course its pretty dangerous stuff. Any test gear you use presents you with an opportunity to sample the volts first hand so better let someone with proper gear and knowledge to check that side of things.
I know people do things anyway but do one thing and make sure you are never alone when working on this stuff.


Electrician's Arms
And finally, can anyone recommend a good electrical testing and training school around the hampshire area.
Brian Scaddan Associates in Waterlooville

IIRC Brian Scaddan was instrumental in devising many of the exam questions, enjoyed by many budding electricians, asked by C&G. He has also written several definitive books on electrical installation work.

Deleted member 26818

From what I understand, Brian used to write all the questions for the 2391, then they got in a team a few years ago, and the questions all started getting weird and wonderfull.
To answer the OP, you should get 230V between each of the three phases and earth, and 400V between any two of the phases.
As for the charger, could you re-connect the connectors and then using a couple of thin probes, measure the voltage across the two pins of the plug.
What voltage is it you are expecting, and should it be d.c. or a.c.?


Solar Guru
In a recession
Try doing a continuity test on the lead plug end to spade end this way it won't be plugged in and you will be able to come back on here as you won't be dead!! Lol
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