shower electrics

[johnbikemad]

my dauguter has a 9.5kw electric shower, mains cable is 10mm guarantee just run out no water comes out i took the main cover off and noticed that on the terminal block that the blue neutral wire was burnt qite bad but the brown live was ok anybody got a clue whats possibly happend, previously its been fine since its been fitted thanks

[scotman]

Agree with DocS that one cable burning indicates bad connection since new. My understanding is 10mm cable is OK for 40Amps. Assuming correct installation everything should be fine. Get an electrician to check it out and ensure appropriate circuit-breakers in consumer unit etc.

[BRIGHT SPARK]

Sounds like you dont need a new shower just a new terminal block.Get a REGISTERED electrician to sort it out.He should carry out an earth fault loop test and an RCD test to confirm all is well.

[buildersmate]

As per BrightSpark (who I reckon is a registered electrician himself).
Doc's comments not helpful. These devices have to be wired using a separate circuit to anything else, back to the Consumer Unit. On a normal domestic supply of 100A, there is no way the lights would dim when the shower is on.
A poor connection caused it, and because the poor connection had additional resistance, excess heat was created that burnt the connection block (it did not arc).

[buildersmate]

Any dimming effect less to do with the local sub, more to do with the size of the cabling and distance from the sub to the eventual domestic user's CU, I suspect. Mine is certainly 100A and every other modern one I've seen is similar.
It's a fair point, though. Shall we call it a draw?

[johnbikemad]

Thanks everyone for your replies ,the person who fitted the shower was an electrician but not an NICEIE registered any way, only six months ago the house had a new consumer unit fitted /upgraded so i could sell the house to my daughter and the whole system was tested by an NICEIE electrician and a certificate issued i have every confidence in this contractor as he does contract work for an enegy company, so i think the bad connection would be suspect as i was feeding his horse carrots while he was doing the work. LOL. cheers everyone