Deciding to replace my consumer unit, the board I am replacing is not a split board and the incomer has a 80A 30mA RCD.
In the past suffered nuisance tripping, do I go for a 80A 100mA RCD, or perhaps a split board. Alternatively what if I use an 80A isolator(no RCD). with MCBâ€™s on lights etc and individual RCBOâ€™s to protect my 2 ring mains and the shower unit. All advice gratefully received.
first thing is what method of main earthing cos if it's TT (rod) you must have rcd @ at least 100mA on incoming sw. in which case split bd with 100/30mA rcd's the only way.
If TN then it's a ? of priorities as I see it, I like RCBO's on power circuits, showers etc. but have had difficulty in finding them rated over 32A for most makes of CU.
'Nuisance tripping', can happen sometimes when lamps blow due to inductive surge i'm told altho' quite how that works I have yet to find out!
but good enough reason for not having lights on RCD circuit, this could be interesting next year as draft 17th regs say ALL circuits for bathrooms must be on RCD, even lights!
If tripping caused by other reasons then indicates fault which needs investigating anyway,
So really no straight answer i'm afraid, but i tend to go with your 2nd choice if poss, regards
SPARX To give you additional information the main incoming United Utilities main fuse has a label on its earth terminal block which reads "PME EARTHING SYSTEM TERMINAL". would this affect your choice. Thanks O-T-H.
Hi agn. PME = tn-c-s to is type of tn system so all I said valid,
Have to point out b4 someone else does 'this is Part P notifiable work' so either pay fee, get local authority bldg. control approval b4 starting or get registered leckie to do work,
Thanks SPARX, intended to use a registered electrician to carry out the work, just wanted to bring myself up to speed and hopefully ensure I replace the existing CU with the best possible option. I have sourced both 32A and 45A MK RCBOâ€™s. So at the risk of being a pain, which would you go for.
Split board with 80A 30mA RCD,
Split board with 80A 100mA RCD
None split board 80A isolator and with RCBOâ€™s on all potentially hazardous circuits.
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