Name and shame!
Shower trips the fuse on the consumer unit
- Thread starter Llarius
- Start date
Name and shame!
Sponsored Links
That type of Wylex MCB isnt available anymore, The nearest match that wholesalers supply around here (Manchester) is Proteus , I`d guess the Board is at least 20 yrs + old , If I`d have done the job , I would have preferred to use a standalone Consumer Unit , to supply the Shower.
Lucky
Interestingly it was the plumbers who suggested this may need to be done, not the electrician (they said that before they contacted him, just to warn us about the cost implication).
I think that's what I'm going to discuss with the electrician when he comes round.
I think that's what I'm going to discuss with the electrician when he comes round.
http://www.tlc-direct.co.uk/Main_In..._NN_Range/index.html#MCBs_for_Wylex_NN_Boards
Brand new
Only up to 40amp though...
Brand new
Only up to 40amp though...
Sponsored Links
It's certainly anything but 'fine', but nor should it really be a reason for MCB tripping ....
...a B40 MCB should be able to carry 45A (10.8kW at 240V) indefinitely without tripping. Even if the shower managed 10.8kW at 230V (i.e. ~47A), which I very much doubt it would, it should still take a very long time (well over 2 hours) to trip a B40.
...but it certainly is not an aceptable, or reg-compliant, practice to have an MCB rated for less than the circuit's load current - so definitely not 'fine'!
Kind Regards, John
I always install a 50A supply for 10.8kW showers. It saves all this hassle, and 50A breakers are readily available straight off the shelf at the wholesalers.
If the existing CU won't take a 50A breaker, then it's up to the customer as to wether they want the whole CU replaced, or the tails splitting and a stand alone unit fitting.
Bodging jobs always comes back to bite you sooner or later.
If the existing CU won't take a 50A breaker, then it's up to the customer as to wether they want the whole CU replaced, or the tails splitting and a stand alone unit fitting.
Bodging jobs always comes back to bite you sooner or later.
And LOOK at the Price of them !!!
What would happen if there was a voltage drop?
Say 220volts, that's 49 amps..how long would a 40a mcb pass 49amps?
Just a thought...
For me as the uninitiated, can you explain to me what that would do/how long it would take, and what might cause that?
It doesn't work like that - this is simple GCSE physics. A shower is a dumb (passive) heating element that can't compensate for a lower voltage by increasing the current so as to achieve the power stated on the box (i.e. 10.8kW) - so, if the voltage falls (to 220V or whatever, the current would also fall, not rise.
The 10.8kW rating very probably relates to the power that would be achieved at 240V (they do that to make their showers sound more powerful). That would be 45A. If that were the case, then as the voltage fell below 240V, so would the current fall below 45A.
Kind Regards, John
It doesn't work like that.
Current and Wattage(Power) increase and decrease with voltage on resistive loads because the resistance (impedance) is the only constant.
10800W @ 240V = 5.33Ω (P = V x R)
The current would rise if the voltage rose to 245 or 250 (46.9A @ 250V).
It's nice to see that (at least) some of us remember how Ohms Law works! 
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
