Does a consumer unit need to contain a main switch?

Most consumer units are installed with some form of isolator or main switch. Does the isolator have to be inside the actual consumer unit, or can this be a separate device such as a rotary isolator?

We asked Shahid Khan, technical manager of the electrical contractors association ECA to help with this question.

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eFIXX Q&A - Questions are selected from electricians comments posted to our videos or social media posts.

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🎦 Presented by
Joe Robinson - technical editor eFIXX

#efixx #morepower #bs7671

[sandymcnair]

Not a ridiculous question as Isolation external to the enclosure is permitted in many applications, but I don't feel there was a full answer given. The answer was only given to BS7671 and BSEN 61439-3 referenced. What does BS EN 61439-3 say? My assumption is that, as this is for operation by normal persons that the Isolation Switch must be provided integral to the CU.

[vasilios.v]

it would be nice if there where written below in the description the answer of the question

[gbelectricks]

Thanks for the info joe👍
Here’s a question, if a 3 phase supply to a final circuit, has to be fed off a linked 3phase mcb, so the loss of one phase would cause the other two phases to isolate.
In an industrial setting, if the 3 phase board is a bs88-2 cartridge type. Then the loss of one phase would not cause isolation of the other two phases, how is this permitted in an industrial setting with this type of DB, and what regulation(s) relates to this situation?

[stuartbrown]

Hi. Can you change the main switch to an RCD to save on space in the CU. I have seen an RCD on a CU without a main switch but no sure if this was correct, I have been asked if this is possible but am not sure of the answer?

[johnavery]

I have a question please? 16 sq mm earth cable needed for a consumer unit (either to an earth rod or main earth terminal), but if I only had 10 sq mm cable could I double up and run two 10 sq mm earth cables, making 20 sq mm in total? Should one cable come loose or be removed accidentally, there would still be a 10 sq mm cable in in situ.

[tom_programator]

Answer this question for me if you know?why in england dutch germany we use curve b and in france italy we use curve c, What is the use of the 1p + n circuit breaker,
and why monopolar circuit breakers are used in some countries and in others 1p + n?

[johnstancliff]

so, heres a good question, here in North America, we have what is called a meter main. does europe have anything like this? its a main switch for the building thats mounted outside on the wall, and had a watthour meter socket in it. they are made in 100, 200, and 400 amp versions and they are a main cutoff for the whole building . they feed a subpanel, or panels... depending on configuration. does the UK, or any part of europe use anything close to what we have here inh North America, or is the main switch always incuded in with the main consumer unit?

[acelectricalsecurity]

on single phase installations the main switch is double pole, yet on a 3 phase installation quite often it's only 3 pole, with the neutral a solid connection, and as it's a live conductor shouldn't it always be isolated.

[jamesdyas]

Can’t think of a reason why you’d particularly want to not have a main switch integral to the consumer unit on domestic single phase. Never really thought about it.

[andrewlougher-harris]

why are the rcbo's overheating and are still in use while not fit for purpose

[hectorheath]

Not a clear answer, it's the reasoning behind it we're after not regulation gobbledygook.

[johnflower]

If a consumer unit is fitted without a main switch what provision would be made for terminating supply cables.

[johnxenofontos]

Hi its John, how do i carry out a PSC test between phases with a Megger 1741.