Cant find fault!

[rob121]

Hi All,
First just wanted to say I passed my domestic installer a couple of weeks ago, so a big thankyou to al those who gave me advice and helped me out when I was a bit puzzled. So again thankyou!

Anyways back to the post, got callled to a job yesterday where the landlord had told me the tenant had complained that the "low level sockets" in the kitchen had stopped working. Anyways turns out its the sockets that supply the dishwasher and fridge/freezer. The house has only one ring supplying all sockets (built in 2004, new builds for you!), then off this ring theyve put a three gang switch, which supplies them and the washing machine.
So plugged my socket tester in and everything seemed okay, plugged dishwasher in - everything okay. So done IR tests, rcd trip test, cont test - again, everything fine. Took the switch and sockets off, no dodgy connections or anything untoward.
I cant see the customer had made a mistake either because he told me he left it for 10 minutes and still nothing, so hes pulled the dishwasher and fridge out, connected above worktop and volla it worked.
Has anyone got any ideas what it could be?

The only fault I found was that the three gang switch was rated at 20AMP fed of the 32A ring. Maybe its getting a bit warm inside and theres a dodgy connection inside?! Oh and forgot to mention that the dishwasher AND fridge went off both at the same time, and theyre fed seperately from the switch.

Interesting to see a new build with a 10mm main earthing conductor on a PME aswell :hurray:

Regards,

Rob

 

[telectrix]

think you're almost there. grid switches breaking down under load. poor internal connection. replace with MK. you'll have to change all of them along with the yoke and faceplate.

 

[malcolmsanford]

Can't be the load breaking down the 20amp grid switches unless the fridge and the W/m have 32 amp CEE sockets fitted to them.

I assume they have normal 13amp plugs tops on the appliances. So I can't see those switches being overloaded. Just because the supply to those switches are off the 32amp Ring Final, don't mean anything

Looks like it was that loose connection, that was most likely there since day one, or perhaps some work as been done on the tiles/wall and loosen it.

 

[telectrix]

i was thinking dodgy connection, but the OP hasn't mentioned anything about one, so i assumed the dodgy connection might be inside the switches, or the terminations to them.

 

[Rockingit]

On the basis that the simplest answer is invariably the right one - loose connection!!

 

[telectrix]

but my view is that as the OP said all the connections were sound, then the poor connection could be the actual switch contacts. i've replaced several cheap switches for this very same fault. even come across some that had been bridged out.

 

[Deleted member 26818]

Those 3gang sockets are fused.

 

[telectrix]

i thought he had a 3 gang grid switch. feeding separate sockets

 

[Deleted member 26818]

So if one switch works, and the other two don't, it would suggest a problem with the wiring of the switches.
It may be that the switches have been incorrectly wired, should be one leg of the RFC to the first switch, loop to the other switches and then the other leg of the RFC to the last switch.
They've probablly wired the switches, so the second two are spured off the first, and either the conductor or the termination has given up the ghost

 

[ackbarthestar]

Yep, I've seen this at the 20A grid switches used to supply separate radials to kitchen appliances. Often the box isn't deep enough and only way of connecting all of the appliances is to loop in the live and neutrals across each switch connecting the ring at one end only.
A continuity check across each of the radials and switches would be the first place to start.

 

[Deleted member 26818]

Unfortunately, that then effectivly means that you are spuring two sockets off of one.

 

[ackbarthestar]

Unfortunately, that then effectivly means that you are spuring two sockets off of one.

That may well be the case, but that is what one sometimes will find. Just check that the ring starts at one end and ends up at the other with phase/neurtal looped in across the switches.
Using double pole switches used in this manner on rfcs was quite common 10-15 years ago.

 

[Deleted member 26818]

That may well be the case, but that is what one sometimes will find. Just check that the ring starts at one end and ends up at the other with phase/neurtal looped in across the switches.
Using double pole switches used in this manner on rfcs was quite common 10-15 years ago.

Yes that's how it's should to be done, but as you said in your previous post, often it isn't.

 

[rob121]

Thanks for the replies.

No loose connection was found! All the terminals were checked and nothing wrong there. The switch is wired properly (suprising enough) with ring coming in one end, links accross then ring leaving at other end.

I do think the switch has the potential to be overloaded as you have 3X 13A appliances on a 32A ring with the switch rated at 20A. I know they arent going to be running at 13A but perhaps start up currents on the washing machine/dishwasher could be causing overheating and maybe a poor connection inside?! Dont think it would make a difference but theres only 1 32A ring that feeds the whole house, kitchen included. But cant see this would cause the two sockets to stop working.

So far ive given the customer a report on what I found including the 20A switch not suitable for 32A ring-recommended changing for 3 X fcu, and obviously made the customer aware of the earthing conductor being undersized. What code on a PIR would that be? (Undersized main earth).

Thanks again, Rob

 

[vernam616]

Is there power leaving the switchs?

I find it amazing how you gained domestic installer and cant work out basic faults like this, sorry if that sounds harsh, but it seems they give anyone a domestic installer