TT system,
- Thread starter Richard1
- Start date
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you shouldn't export an earth, depending on the main installation if it's TNCS your best way would be on a split load board non rcd side(main switch) and then fit an rcd garage consumer unit on a TT system. this avoids nuisance tripping
The main system is TT, the customer has requested a new consumer unit,
currently the garage is fed by a 2.5mm T & E which I beleive is contary to BS7671, I intend to fit 100ma TD RCD main isolator. followed by a split load board with 30ma RCD protection, How ever the garage is detached and stands 6m away from the main house
currently the garage is fed by a 2.5mm T & E which I beleive is contary to BS7671, I intend to fit 100ma TD RCD main isolator. followed by a split load board with 30ma RCD protection, How ever the garage is detached and stands 6m away from the main house
have you considered
house meter-
tail block-consumer unit
then
tail block RCCB TD 25mm swa which de-rated as buried in the ground will feed a 63 amp garage consumer unit
Also by using RCCB you have covered yourself for both kinds of fault situation
100ma for supplementary protection
63a rccb will cover overload protection and provide positive discrimination
house meter-
tail block-consumer unit
then
tail block RCCB TD 25mm swa which de-rated as buried in the ground will feed a 63 amp garage consumer unit
Also by using RCCB you have covered yourself for both kinds of fault situation
100ma for supplementary protection
63a rccb will cover overload protection and provide positive discrimination
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Yes earth rod as not exporting earth 
no I mean RCCB as main switch for submain
http://www.ceepower.co.uk/RCCB's.htm
A Residual Current Breaker with Overload (RCBO) is a combination of an RCD and a miniature circuit breaker (MCB) would be retro fitted on say a TNCS system if you only had a spare way on split load on main switch side.
Please before you suggest I don't know what I'm talking about try googling the term.
As for not knowing the term RCCB these are used extensively in mobile wiring for show power (GE CAPITAL AND AGGREKO) more popular abroad
I've 2381,2391 and am registered with Elecsa
great pdf dealing with garages
http://www2.theiet.org/Publish/Wire...matters_electrical_installations_outdoors.pdf
http://www.ceepower.co.uk/RCCB's.htm
A Residual Current Breaker with Overload (RCBO) is a combination of an RCD and a miniature circuit breaker (MCB) would be retro fitted on say a TNCS system if you only had a spare way on split load on main switch side.
Please before you suggest I don't know what I'm talking about try googling the term.
As for not knowing the term RCCB these are used extensively in mobile wiring for show power (GE CAPITAL AND AGGREKO) more popular abroad
I've 2381,2391 and am registered with Elecsa
great pdf dealing with garages
http://www2.theiet.org/Publish/Wire...matters_electrical_installations_outdoors.pdf
But an RCCB/RCD does not provide overload protection, which is what JohnD has picked up on. An RCBO is the closest device to what you seem to think he needs that will provide overload protection.
RCCB are avaliable as current setting, some are fixed and some such as Merlin Gerin are can be set on amp trip eg 45amps 500ma
just one example
http://www.merlin-gerin.com/MG/en/products/index_fon1_fam57_M9_DPN_Vigi.htm
we always get rccb's with overload protection, if you do not ask for this you will get rccb without any overload protection. a while back a merlin gerin rccb with overload was fitted to an installation and used as main service cutout and fire protection(500ma and load set as 45 amps and then tag sealed)(this was france and not by myself-but complied with local electricity requirement)
personally I think service cutout fuses are old hat and rccb with overload protection is the way forward
just one example
http://www.merlin-gerin.com/MG/en/products/index_fon1_fam57_M9_DPN_Vigi.htm
we always get rccb's with overload protection, if you do not ask for this you will get rccb without any overload protection. a while back a merlin gerin rccb with overload was fitted to an installation and used as main service cutout and fire protection(500ma and load set as 45 amps and then tag sealed)(this was france and not by myself-but complied with local electricity requirement)
personally I think service cutout fuses are old hat and rccb with overload protection is the way forward
RCCBs are generally what everyone referrs to as an RCD, an RCD being a generic term which covers all the different types. RCCBs do not provide overcurrent protection on their own. RCBOs are a combination of an MCB and an RCD which do provide both functions.
Bit of bedtime reading here: http://www2.theiet.org/Publish/Wire...iring_matters_inspection_and_testing_rcds.pdf
Whats wrong with service fuses? Not a lot to go wrong with a piece of fuse wire
Bit of bedtime reading here: http://www2.theiet.org/Publish/Wire...iring_matters_inspection_and_testing_rcds.pdf
Whats wrong with service fuses? Not a lot to go wrong with a piece of fuse wire
lets be perfectly clear about this, the rccb with overload protection are not rcbo, they are similar in size to a fused main switch not the size of an mcb.
Secondly in terms of fault this system is better at sensing faults compared to a fuse and disconnecting quicker
Secondly in terms of fault this system is better at sensing faults compared to a fuse and disconnecting quicker
So what is the difference between an [RCCB with overcurrent protection] and an RCBO? RCBOs also come in double module width as double pole devices.Aardvark Avo said:
Why would protecting a whole installation with a single RCD be safer than individual RCDs though?
my view is
rcbo is mcb with rcd,single pole
rccb double pole or 4 pole with or without overload protection
but either way call it what ever you like
never suggested that it was one rcd device, what I suggested was that the house was on a 30ma rcd protected consumer unit as tt installation.
from the tail block to protect the submain a 100ma rccb time delayed with over current to protect the sub main.
the garage would then have rcd protected consumer unit at 30ma for supplementary protection against direct contact tt install.
the end
rcbo is mcb with rcd,single pole
rccb double pole or 4 pole with or without overload protection
but either way call it what ever you like
never suggested that it was one rcd device, what I suggested was that the house was on a 30ma rcd protected consumer unit as tt installation.
from the tail block to protect the submain a 100ma rccb time delayed with over current to protect the sub main.
the garage would then have rcd protected consumer unit at 30ma for supplementary protection against direct contact tt install.
the end
It may be your view, but not the view of everyone else on here. An RCBO as stated before can come in different configurations, single pole, double pole etc. As you can appreciate terminology is very important in this job.Aardvark Avo said:
OK, I'll call an RCCB an RCCB just like the IET call it.
You posted before:
That implies the DNO service head.
Like I said before, terminology is very important. It may be if you have worked on the continent the terminology is slightly different.
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