It should be at least SPSN, if not DP which is what I originally said, because leaving a N-E fault present is short sighted in my opinion, which is what the vast majority of RCBOs do.
because if you get a N-E fault this will of course trip the up front SP RCBO device, however by being SP will leave the N-E fault still present.
Now if this was a farm or agricultural install this will also trip the front 300mA RCD required for fire protection, with no means of being to isolate...
Forgetting for a moment the last paragraph in reg 536.4.202 which I will come back to.
That reg still states it is the IB or design current that we should be designing to, which fair enough we always did, at least the better sparkies did.
Now one manufacturer tells us we were all wrong ? it...
As I said, we always had to design around a split load board, ie. we divided the circuits up and tried to load split anyway, just the regs never explicitly said we should, although this was common? sense to anyone sparking professionally.
Are you telling me that say 3X 32A breakers plus a few 6A for ligting are going to exceed the 100A mains switch not to mention the absolute max of a 100A BS1361 type 2 incoming fuse ?
And another thing the RCD is not a OCPD so as long as you stick below its design current Ina things should be fine, and no you cannot just add the breakers up as that would have a massive knock on effect wrt to diversity, The effing IET don't there ar*e from their elbow.
CIBSE should take over...
Yes I know, however the same regs also state manufacturers instructions shall only be taken account of ;) they cannot have it both ways. don't you just love the IET :)
Which reg states that though Ian ? 536.4.202 doesn't as far as I read it, Hagar is only one manufacturer out of many.
I normally take what you have to say seriously as you are one of the few that happens to know what you are talking about.
I had a look at the corrigendum for the 18th (yes...
Not always, the cheapest quote may come from someone who is good but may be just starting out and/or small and will do an exemplary job, othoh you could get someone whom is basically taking p**s and charging high and sending shall we say "operatives" out and charging premium rates.
Seen it done.
I disagree Tel,
It could have been done at short notice, plus I don't agree with slagging another spark off without giving a right of reply, unless it was a total abortion from the beginning, you should know me by now, price does not come into at this moment in time
Oh I don't disagree, a full RCBO board is always nice to have if the customer will go for it, however they should always have been DP, or at least SPSN from the get go for obvious reasons.
Read Reg 536.4.202 again, and you will see it is the design current Ib that needs to be complied with, which is what most of us have always done anyway.
As said manufacturers instructions should be taken account of, not followed blindly.
Ps. Spin London was correct too it is also the ICn that...
Unlikely to hit 9mA in a domestic environment, besides which if you hit 10mA on a given circuit you are then into HI earthing, we hit this on office installs quite frequently where a lot of computers are installed.
Edit: 30mA RCDs tend not to trip until circa 22mA mark, @ 15mA they should not...
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc