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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?
It might be worth use of a "shower priority unit" these are primarily intended for connection to two electric showers so as to prevent simultaneous use. I have used these units for other large loads.
Get one that gives priority to shower number one. Connect the cooker to the "shower one" terminals and the shower to the "shower two" terminals. The cooker can then be used as normal, but the shower will be isolated when the cooker is in use. The shower may be used as normal provided that the cooker is not in use.
Or a manual changeover switch as previously suggested. These are widely sold and primarily intended to connect an installation to either mains supply or to a generator, but never both. They can also be used to connect a single supply to either of two loads, but never to both loads.
Yes I have a 40A circuit breaker in the consumer unit. Presumably an MCB changeover switch is something which sits in the consumer unit? I would actually need a switch downstream of that - i.e. in the kitchen/bathroom - as I would want to switch the supply between two appliances on the same circuit?
A 40 Amp M.C.B. is a miniature circuit breaker. You referred to a 40 Amp R.C.D. I assumed that you meant an M.C.B.
The changeover switch will not be located in the consumer unit, it is too big. It will be installed downstream of the origin of the circuit.
Yes I have a 40A circuit breaker in the consumer unit. Presumably an MCB changeover switch is something which sits in the consumer unit? I would actually need a switch downstream of that - i.e. in the kitchen/bathroom - as I would want to switch the supply between two appliances on the same circuit?
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?
Presumably you have a 40 Amp M.C.B. A changeover switch will allow only one of the loads to be used at a time.
Here is an example of a big 100 Amp version. I am sure that small versions are available say rated at 45 Amps.
