voltage/current tester

redmoose · 28 Aug 2006

Problem: Electric shower has failed. It is as if the power supply has been cut off.

So far I have checked the consumer box and the fuse of the shower socket. Both are fine. Before I replace the shower unit I want to check that the transformer that takes the mains 240v and reduces to 12v for the shower hasn\\\'t failed. Therefore I want to check the output voltage of the transformer.

Here is my question.
I have never used voltage or current testers. They are different beasts aren't they?
Could somebody give me a quick run down of how they work and their uses.
Also which one do I need here - presumably I need a voltage tester, because the shower doesn't work then there will be no current.
Any help appreciated.
Have tried researching on web, but am unable to get the info I need.

Thanks in advance.

securespark · 28 Aug 2006

Your best bet is to buy an inexpensive multimeter that will cover at least AC 12V up to 400V and DC 1.5-24V

You need as you say to start at the beginning - is there 230V leaving the consumer unit.

Does it arrive at the primary (230V) side of the tranny? Is there 12V (assuming it steps down to 12V) on the secondary side?

Worth looking on tranny or in instructions to find out whether output is AC or DC.

redmoose · 28 Aug 2006

Hi securespark. Thanks for the reply.

The transformer steps down to 12v DC.

I have seen these multimeters for sale in maplin for a few quid.
Can you give some information on them.
Do they measure voltage or current.
Do they have a lcd display.
Presumably, if they measure voltage then you test the live terminal, and not the neutral terminal.

securespark · 28 Aug 2006

You measure voltage across two conductors, either L & N or L & E or N & E, or in the case of 3 phase, any of the lives.

You cannot measure voltage with a multimeter without two connections.

breezer · 28 Aug 2006

Since you said

redmoose said:
I have seen these multimeters for sale in maplin for a few quid.

why dont you buy one and read the instructions.

redmoose said:
Do they measure voltage or current.

Both

redmoose said:
Can you give some information on them.

Buy one

redmoose said:
Do they have a lcd display

funy, i thought you said

redmoose said:
I have seen these multimeters for sale in maplin

redmoose said:
Presumably, if they measure voltage then you test the live terminal, and not the neutral terminal

You presume wrong

Put it this way, I admire you for asking (thats a good ting) but would you expect to put a nail in with a shoe?

so do not expect to be able to test / check anything electrical wih out a multimeter.

as you said you can get one for a couple of quid

Taylortwocities · 28 Aug 2006

Do not even try to measure current unless u know what you are doing. You can test all that you need to by using the voltage ranges.

In the current test position the meter is effecively a short circuit so if you put this across live and neutral or the output of the transformer then you'll probably knacker one or more of the following:

the meter
the fuse,
the transformer
you

Steve · 28 Aug 2006

Taylortwocities said:
Do not even try to measure current unless u know what you are doing. You can test all that you need to by using the voltage ranges.

In the current test position the meter is effecively a short circuit so if you put this across live and neutral or the output of the transformer then you'll probably knacker one or more of the following:

the meter
the fuse,
the transformer
you

the leads on my multimeter claim to be worthy of 400mA - this is no way enough to test anything except maybe earth leakage. Dont attempt to measure current used by any appliances though - your meter will explode

Just use it for voltage and continuity.

plugwash · 28 Aug 2006

i think my meter claims 10A for 5 seconds or something like that.

Taylortwocities · 29 Aug 2006

Also, when measuring current you will, by definition, be bearking into the circuit and doing the tests LIVE.
You'll need properly insulated clips on your meter to do this (not usually supplied with a £3 meter.
Don't do this unless you know what you are doing..

sm1thson · 29 Aug 2006

redmoose said:
The transformer steps down to 12v DC.

are you sure? transformers are ACin ACout you need a few extra bits to get DC. if you set your meter to DC and its AC then it will read about 0V -so if you are measuring AC you need it on AC!

redmoose · 4 Sep 2006

Bought an inexpensive multimeter and established that the electric circuit is fine. (Thanks Securespark for the advice)
The transformer does stepdown from 240v Ac to 12v DC.

The problem is in the water mixing valve of my Mira Supajet. I need a replacement. Trouble is that they don't make the shower anymore, they do not supply spares anymore, and the three of four shower spares websites that I have found do not carry this spare.

My question is. Does anybody know of any company that does second hand shower parts? Any help gratefully received.

BTW, the reason that I am going to all this trouble and not buying a new one is that the existing shower is recessed into the cubicle wall. I have been unable to find a new unit which would slot in. Therefore we are talking major works.

Adam_151 · 4 Sep 2006

redmoose said:
The transformer does stepdown from 240v Ac to 12v DC.

In that case then its not a transformer, its a power supply, a device which a transformer may or may not make up a significant portion of

redmoose · 4 Sep 2006

Ok. Let me try and knock this on the head.

The label on the 4inch cubed box reads.

Mira SupaJet 100 series transformer.
Power unit for indoor use only.
240volt AC 75VA 50Hz 11.5volt DC output.

So...My question is. Does anybody know of any company that does second hand shower parts? Any help gratefully received.

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voltage/current tester

breezer

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