Mains wiring a house (UK)

[solwisesteve]

Some guy in the office said the regulation method of UK house wiring is now a separate spur from each socket back to the CU with an MCB per spur. This is the method that's popular on the continent e.g. France. It means a heck of a lot of mains cable is used and a HUGE CU is required; fuse per socket. On the other hand the mains flex used doesn't have to be as thick as normally used on a ring installation. Also he says that twin-and-earth is no longer used with individual separate wires running from each socket back to the CU. Is this right?

[Bluehase284]

All poppycock.

There is no single way of wiring specified in part P of the building regs or in BS7671:2018 - the current edition of the UK wiring regs.

You can wire in ring, radial, spur and provided that the cable is appropriately rated, protected for overload and RCD faults then you can use any method you want.

You can use single cable in conduit (normal in some commertial work) or twin and earth as you see fit - again select cable to suit the situation.

Design the system to meet the need - can you wire as you described within regs? Yes. Why would you? If each circuit is on RCBOs then you only ever trip that circuit. If you trip a circuit in a domestic install regularly then you either have a bad install that is underrated, or faulty equipment.

There are limited times when medical equipment, servers are put on their own circuits but beyond that I don't see why you would want or need to.

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[solwisesteve]

Cheers :-)

Sounded like a bit of tosh!

[adrianw]

I thought the regulation was the number of spurs must not exceed the number of outlets on a domestic ring main.

[solwisesteve]

I thought the regulation was the number of spurs must not exceed the number of outlets on a domestic ring main.

The french way is a CU with a fuse per spur. Each spur to a single socket (I assume a double wall socket would be okay - I don't know though).

[Bluehase284]

The french way is a CU with a fuse per spur. Each spur to a single socket (I assume a double wall socket would be okay - I don't know though).

I'm not entirely sure that it is true that the French do this...
That do tend to not use rings and wrote everything in radial with a separate MCB.

FYI a spur is a t joint into an existing circuit - so I think you are referring to radial wireing, hence the comment about numbers of spurs above.

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[solwisesteve]

I'm not entirely sure that it is true that the French do this...
That do tend to not use rings and wrote everything in radial with a separate MCB.

FYI a spur is a t joint into an existing circuit - so I think you are referring to radial wireing, hence the comment about numbers of spurs above.

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Yes that's what I meant ;-)

[W124]

You can download the Part P overview here :

https://www.gov.uk/government/public...ved-document-p

If you want the detailed IET electrical regulations, you can find the recent field installer guides on eBay.

IIRC the yellow covers are the latest version.

Google part P for endless poorly informed online discussions on how to interpret the regulations.

[-Ally-]

That guy in your office is dangerously ill-informed.

[vortgern]

That guy in your office is dangerously ill-informed.

Better sign him up here and get him in the BP!

[MCFastybloke]

Is he foreign?

[solwisesteve]

You can download the Part P overview here :

https://www.gov.uk/government/public...ved-document-p

If you want the detailed IET electrical regulations, you can find the recent field installer guides on eBay.

IIRC the yellow covers are the latest version.

Google part P for endless poorly informed online discussions on how to interpret the regulations.

Cheers.... Blue cover I think.

- - - Updated - - -

That guy in your office is dangerously ill-informed.

What do they say 'a little knowledge' ? :-)

[IAmATeaf]

That guy in your office is dangerously ill-informed.

I’ll-informed yes but dangerous?

[-Ally-]

I’ll-informed yes but dangerous?

This

What do they say 'a little knowledge' ? :-)

[scottbombedout]

The guy in your office doesn't have a habit of pooing through letter boxes does he?

[Pennywise]

Cheers.... Blue cover I think.

- - - Updated - - -



What do they say 'a little knowledge' ? :-)

Blue it is




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