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B

beaver74

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in a t.t system i have all way thought you need a 100mA s type dp rcd covering the whole installation
been to a job today and it is a standard board dp isolator and filled with rcbo's which yes they will protect as for high earth loop but they are only single pole am i right in my thought's
 
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K

KFORDHUNTER

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  • #2
My thoughts are that if every circuit is protected by a 30ma rcbo what is the need for a 100ma main rcd. I thought the 100mA rcd was to protect all "other" circuits when you could still have circuits on mcb only.
 
B

beaver74

  • Thread Starter Thread Starter
  • #3
My thoughts are that if every circuit is protected by a 30ma rcbo what is the need for a 100ma main rcd. I thought the 100mA rcd was to protect all "other" circuits when you could still have circuits on mcb only.
yes but i am thinking that rcbos in general are single pole as apossed to double pole main rcd
 
in a t.t system i have all way thought you need a 100mA s type dp rcd covering the whole installation
been to a job today and it is a standard board dp isolator and filled with rcbo's which yes they will protect as for high earth loop but they are only single pole am i right in my thought's
This configuration of board is probably what the IET intended to be the norm with regard to 17th Ed compliance. Can`t see a problem with it myself.
 
Y

YTSOxford

  • Thread Starter Thread Starter
  • #5
Its a very expensive way of doing it tho! U can get DP RCBOs but they take up 2 modules; I used a 30ma to protect swa running a supply out to a garage.
 
I agree that a board full of rcbo`s is way too expensive for many jobs in the domestic sector - the dual rcd boards are far more viable. Cost aside, rcbo`s just take up too much room in the currently produced boards!
 
B

BillR3

  • Thread Starter Thread Starter
  • #7
Most manufacturers now make single module RCBO's, Merlin Gerin and Wylex being the ones that I use on a regular basis.
 
I was under the impression that rcbo's were all double pole.That is why you have to connect the neutral into them and why there is a curly blue
lead hanging out of them-all I have seen and used have also been one
module type.Incidently they can be bought for around 15 quid a pop.
 
The neutral on most rcbo`s is for functional purposes but is NOT usually switched, hence the single pole designation.
 
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