Wiring questions..

[Sirbendy]

Last night, I knocked off our immersion at the fuseboard. It was either that, or try to fight the airing cupboard door, which was installed handle-less by the last owner, as it binds BADLY on the carpet, with my kids asleep. No contest.

The house is a 50's wimpey concrete job, rewired when council in 1997. Still got the stickers on it.

Now, I was mildly surprised when running a bath for the kids tonight that the bathwater wasn't hugely warm. Yes, the immersion is off. However, the GCH should be dealing with the tank. Why is the house at 17.5 degrees, when the timed setpoint is 19? Ah, the controller is dead.

The fuseboard has the following labels on the switches:
Ring main
Upstairs Lights
Downstairs Lights
Shower
Cooker
Water Heater.
and the main switch. All RCB.

Turned the immersion switch back on, the controls light up, 3 port valve whines and boiler fires.

Is this anything to be mildly alarmed about? The controls/boiler seem to run off a 3amp FCU in the airing cupboard, but this seems to pull power from the immersion circuit wiring.

I'm wondering now if the SELV extractor in the bathroom is run from the lighting circuit as well...it looked about right from the loft..

I can see me doing a little re-labelling..ha..

 

[ricicle]

Sounds to me like the heating system's SFCU is fed from the load side of the immersion switch rather than the feed side which was/is the logical way to do it.

EDIT: Sorry just re-read. You isolated it at the mains so killed the heating system as well. It's pretty common practice to feed the heating controls from the immersion supply as it's the readily available supply in most, if not all, airing cupboards !

 

[EFLImpudence]

Turned the immersion switch back on, the controls light up, 3 port valve whines and boiler fires.

Is this anything to be mildly alarmed about? The controls/boiler seem to run off a 3amp FCU in the airing cupboard, but this seems to pull power from the immersion circuit wiring.

Nothing wrong with it being on the same circuit as the immersion but they should be on separate switches.

I'm wondering now if the SELV extractor in the bathroom is run from the lighting circuit as well...it looked about right from the loft..

Could be. Normally is.

 

[Sirbendy]

Ah, good. That's reassuring then. It's just that the PO had an interesting way of doing DIY.

For instance, installing light switches upside down, and not fitting the wire retaining screws, leaving the wires just pushed into place. Or having the entire utility (6 sockets, a PIR and 2 light fittings) running from an IP65 junction box, to an unmarked fused connection unit behind a cupboard, and from there to everything else.

Took me a while to trace all that out and discover why the whole lot had gone. One very toasted 13amp fuse.

 

[ban-all-sheds]

Now, I was mildly surprised when running a bath for the kids tonight that the bathwater wasn't hugely warm.

It's character-building....

 

[ban-all-sheds]

Took me a while to trace all that out and discover why the whole lot had gone. One very toasted 13amp fuse.

That's why I'm not a fan of fused spurs as a way to allow more than one socket. A 13A fuse will pass 20A indefinitely, but as you have found, they get a bit hot and bothered.