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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?
Sparkingchip: 433 Protection against overload current
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.
8.5 kW @ 230 V = 37 A, so almost a 25% overload. Is that small? Is 25 min a long duration? I personally would view a "small" overload as being one which lies outside the trip curve so the overload could continue indefinitely.
In any event, a 30 A BS 1361 fuse should have been capable of handling 37 A for half an hour, so perhaps something else was going on?
Sparkingchip: 433 Protection against overload current
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.
8.5 kW @ 230 V = 37 A, so almost a 25% overload. Is that small? Is 25 min a long duration? I personally would view a "small" overload as being one which lies outside the trip curve so the overload could continue indefinitely.
In any event, a 30 A BS 1361 fuse should have been capable of handling 37 A for half an hour, so perhaps something else was going on?
