Mains Question

Lounge
1

Hi all.

I know mains has been covered here many times but I’m struggling to find an exact match to my query. We’re having a new kitchen fitted and as we have the old “Wylex” type consumer unit the electrician has said that’s going to need replacing too.

I see the advice that a type “C” curve RCD should be used and also found a thread with this title “Why Naim recommends 100A RCD isolator for HiFi dedicated mains if there is only one 32A MCB in the chain”

Does the CU need to be 100A if there isn’t going to be a dedicated mains for the HiFi, or in that instance do I just need the type “C” RCD? If so, at what rating? 40A has a lot of mentions in the threads I’ve been going through.

I’m basically just looking to avoid tripping the RCD on power up. Thanks in advance for any recommendations.

2

Type C breakers are used to prevent them from tripping when you turn on the boxes that have large power supplies, that’s all. If you have a problem with the regular type B breakers normally used in domestic installations it’s certainly worth asking your electrician to use them.

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3

The consumer unit main fuse will be sized relative to the supply, leave that to the sparky.

For the ring or spur feeding the hifi type C would be best but again must be sized for the cable sized used again leave to the sparky.

4

Useless post unless we know where you are, rules vary around the world.

Martin

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5

Consumer units don’t have fuses (unless they are 50 years old!) Perhaps you are thinking of the fuse on the incoming supply, usually sited next to the meter, which is the responsibility of your DNO and cannot be changed by anyone else.

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6

I’ve always gone on the premise it’s UK unless stipulated. After all that’s where most users are from.

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7

That’s a brave assumption when advising people on their internet about what (not) to do with their mains supply.