A DIY Challenge

Panjandrum · Unread post by **Panjandrum** » 02 Dec 2004, 13:38

To all you expert DIYers out there, here's my problem.
Electric shower with ceiling switch; fed from its own ELCB at the consumer unit.
Turn on the ceiling switch. Wee light on the switch comes on OK. There's live to the inside of the shower. But the power light on the shower does not come on.
Press the shower button. Nothing happens. Wee light on the ceiling switch goes OUT. There's STILL live to the inside of the shower.
Suggestions very welcome.
PJ

nick · Unread post by **nick** » 02 Dec 2004, 16:30

Dodgy switch contacts can give weird symptoms like this. They will allow enough current through to light a small bulb, or show on a voltmeter, but not to run something that consumes huge current like a shower.
I wonder if the contacts in either the pull switch, or the ELCB have partially burned out ?
Is this a new installation, or has it worked before?

nick · Unread post by **nick** » 02 Dec 2004, 16:35

Ah! just had another thought.....
Heavy duty switches like this are usually double pole - ie both the live and neutral are switched. If the neutral contact in the switch was faulty you would still find a live in the shower, and possibly enough current would pass to light the little neon bulb on the switch when the shower itself was off, but not enough to actually power the shower.

Panjandrum · Unread post by **Panjandrum** » 02 Dec 2004, 17:20

nick
Worked fine from April 2002 until now.
Switch is DPDT - your suggestion on faulty contact plausible - though it looks fine from the outside and at the connections (not much of a guide to contact condition).
Nearly drove my brain scatty last night - couldn't believe anything downstream from the switch could make its light go out!
Not my own shower so it will be a day or so before I get to check out the switch etc.
Thanks.
PJ

andycarter · Unread post by **andycarter** » 03 Dec 2004, 01:38

Suspect a poor connection (i.e. high resistance) which is most likely on the neutral wire, somewhere between the consumer unit & the switch, or inside the ELCB.
When you switch the shower on, it has a low resistance - so the 240V is dropped across the high resistance rather than the shower. hence neon indicator on the switch goes out but shower is still live.

bxbodger · Unread post by **bxbodger** » 03 Dec 2004, 16:33

Here's where you will get an answer to this-
http://www.diynot.com/forums/viewforum.php?f=8&sid=

Panjandrum · Unread post by **Panjandrum** » 03 Dec 2004, 18:39

That looks really useful.
I'm fairly sure I know what the problem is now, but I'll give DIYNOT a whizz to see what happens. But it would be hard to beat this forum for helpful info and fast replies!!
PJ

dnsey · Unread post by **dnsey** » 03 Dec 2004, 20:16

To make sure, check the voltage before the switch (switch off, shower off, before the switch (switch on, shower on), after the switch (switch on, shower off), and after the switch (switch on, shower on). All should be the same, give or take a couple of volts. If only the last reading is low, you have a faulty switch. On the other hand, if the second reading is also low, you have a wiring fault before the switch - be careful, it could constitute a fire hazard.

Panjandrum · Unread post by **Panjandrum** » 04 Dec 2004, 05:17

Well I've had an interesting experience with DIYnot. Have to say that the general tone of posts here is immensely more sympatico than there. Good for a laugh though.

Panjandrum · Unread post by **Panjandrum** » 05 Dec 2004, 01:36

Job done. Dead switch - roasted inside on the N side (hey that's beautifully alliterative).
The guys on DIYnot went a bit apoplectic when I confessed to using one of those dinky neon screwdrivers as a test device[:I][:I]
They'd explode in purple rage if they knew I confirmed the fault by connecting a light bulb to the circuit at various places[:D][:D]
Of course they're right, in principle. The right tools for the job make it easier, faster and safer.
But if you ain't got the right tools, the ingenious alternative that works can be extremely satisfying.
And finally, a big vote of appreciation for the general tolerance and affability of this forum.
PJ

Stuart McB · Unread post by **Stuart McB** » 05 Dec 2004, 01:42

Get the Mrs to buy you one of those state of the art testers like mine did. She noticed that my old dial tester was looking a bit batterd, so now I'm up to speed with all the electrics around the house and the car. Wahoo! standback man with rubber multi-meter comimg through.

nick · Unread post by **nick** » 05 Dec 2004, 17:02

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Panjandrum

The guys on DIYnot went a bit apoplectic when I confessed to using one of those dinky neon screwdrivers as a test device[:I][:I]
They'd explode in purple rage if they knew I confirmed the fault by connecting a light bulb to the circuit at various places[:D][:D]
<hr height="1" noshade id="quote"></blockquote id="quote">
Yes, I had a look on there, and at the Plumbing & Central Heating forum. I imagine they wouldn't be too pleased either if I told them I installed a complete gas central heating system 4 years ago with no previous plumbing experience [:D]
Four years on it still works perfectly, as opposed to the Corgi installed system in my mum's house which developed a gas leak 2 days after the Corgi fitters left (they hadn't tightened up a compression fitting on a gas pipe properly), and then an electrical fault with their pump wiring a month later.....(Both of which I fixed 'cause the Corgi fitters were "too busy" to come back and do it.)
Anyway, glad you got your problem sorted ![:D]

Panjandrum · Unread post by **Panjandrum** » 05 Dec 2004, 22:50

I think what happens is that the guys who are genuinely proficient know, from experience, that there is a lot of sloppy work done - some even by DIYers. So they acquire a touch of attitude[8D]
What they don't account for is that experienced DIYers are a lot more careful and methodical than less-capable professionals - because they know the risks, know the boundaries of their competence, and will be living with the results.
I can think of good examples of poor "professional" work in my own direct experience in - well in everything!
Oh yes, and of course there are those who THINK they fall into that category of "genuinely proficient" and slag off DIYers anyway.
PJ

Unread post by **martyhopkirk** » 06 Dec 2004, 00:07

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Yes, I had a look on there, and at the Plumbing & Central Heating forum. I imagine they wouldn't be too pleased either if I told them I installed a complete gas central heating system 4 years ago with no previous plumbing experience [:D]<hr height="1" noshade id="quote"></blockquote id="quote">
Yep - installed mine 9 years ago,(gravity system), also running system through a solid state control box - sort of "or" gate. If room stat calls - heating switches on, if cylinder stat calls, just HW circuit switches in - but means I always have a full tank of piping hot water - might sound wastefull but its not - tank well insulated and takes less time to heat up a little than the whole tank. In 9 years had to use my immersion twice (2 days I spent re piping the whole house radiators in 15mm from 8mm microbloodybore)
Not a difficult job if approached methodically.
Ah the joys of 70's building standards!
Tradesmen eh! waste of time. And whilst Im on about tradesmen - took my car (this is years ago) to a garage to be serviced and have an annoying noise from front wheels sorted.
Car came back without oil being changed (but of course had been charged for this) and with noise still undiagnosed - after i had been to the office and ended up pouring the old oil over the owners desk I found the cause of the noise - the tread was parting company with the tyre. Fantastic service.