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Two high-power appliances on a single 40A RCD
Former Community Member
I have an electric shower installed on a 40A RCD, in a room adjacent to my kitchen. The shower is only used in an emergency - i.e. when our gas boiler is unable to provide hot water to our main bathroom. I would like to take a spur from this 40A connection to use for a new double oven, which is rated at 32A. Can anyone advise on a safe and legal way to do this, ensuring that only one of the two appliances can be connected at any one time?
433.1 Co-ordination between conductor and overload protective device
Every circuit shall be designed so that a small overload of long duration is unlikely to occur.
I replaced a fused switch with a 30-amp cartridge fuse in it after the whole thing blew off the wall, the customers teenage daughter was spending around twenty five minutes in a shower with a 8.5 kW electric shower, her dad kept packs of fuses ready to replace the fuses as they blew, then one day he went into the garage and there was just a big soot mark on the wall where the fused switch used to be.
One person having a shower whilst the oven is in use could end with catastrophic damage to the electrical installation and house.
It is just not worth taking the risk.
Andy Betteridge
Again for clarification: if the proposed solution is for a switch which prevents both appliances being connected to the same circuit simultaneously, doesn't this complete;y remove the risk?
Gosh, what a lot of postings since I looked in a few hours ago! ?
What is the design load? From the sound of it, it is not the shower plus the stove - it is the shower or the stove. The householder knows that. However, an emergency shower for when the gas is off does seem to be a great luxury.
I accept that there is a difference between intended maximum load and possible maximum load, and I also appreciate that some form of switch (change over or priority) unequivocally is compliant. However, has anybody mentioned the D word?
Put another way, you have two 40 A showers, and a 40 A cooker on a 100 A supply. Does that break the rules?
My apologies to the OP if this technical discussion is unhelpful. ?
cfcman dont expect an answer on this forum. However look it at another way if you were to install a seperate circuit for the cooker you may well need to inform your supplier of the additional load, but again this very really happens, an electrician will come along bang in the circuit bill you and go. What you are propossing would seem to be a good idea as there would be no additional load added to the system. Where installations have electric wet system boilers and a shower installed a shower priority switch needs to be installed.
Thanks for clarifying. I guess it was your two earlier statements that puzzled me:
""The kitchen fitter is being quite reasonable and the sensible thing to do is to install an additional complete new circuit for the cooking appliances."
"Just pay to have a new circuit installed for the cooking appliances and do a decent job."
As far as I can see, a £45 changeover switch would render these observations redundant?
