Why do UK consumer units have monopolar disjoncteurs - eh sorry - MCBs

[WilcoxElec]

In France we use Bipolar MCBs everywhere and one advantage is that a circuit can be properly isolated even if Madam has a load in the washing machine while you are doing stuff on another circuit. I have come across cases where a UK style consumer unit has been used in a DIY renovation – and I was replacing some circuits and moving them to a French board . I opened an MCB on the UK unit, and at some point I caused the RCD (DDR !) at the head of the unit to open by accidently touching the Neutral to the Earth – - there was load on the other circuits – and the neutrals are all together in the consumer unit. At the time I supposed that this probably couldn't happen with the TN schema used in the UK, but – thinking about it now – I realise that – yes it would. So – my silly question is "why do consumer units have monopolar MCBs?" They must be cheaper – and of course one should switch off everything at the mains always --- but there does seem to be an advantage to the French set up (if done properly) - if cutting off everything is really really inconvenient.



Please excuse another silly question , just trying to get the number of posts I need for the next level LOL (and avoid doing the paper work I should be doing) :juggle2: .....

 

[telectrix]

it's standard practice in the UK to use single pole MCBs. and common the neutrals on a bar. cost may be the overriding factor here.

 

[oldtimer]

Its just the way the French are yes its a great idea but we are stuck with single pole so if we have a neutral to earth fault then we loose half the board with no way of isolating the faulty circuit until a electrician is called out to trace and sort

 

[Engineer54]

It's not only France that has DP MCB's, the Germans/Austrians (among others) do too, but they are ''needed'' on there Shucko (always unsure of the spelling!! lol!!) socket outlets as they have unpolarised plug tops.

Many of your rural and semi rural installations in France are TT earthing systems, which should really have DP MCB's, or should i say DP/RCBO's to isolate all live conductors. That should go for the UK too, but most electricians in the UK go for the compromise set-up of a dual RCD CU, protecting several MCB's on each RCD device...