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nothing else to say, this is the answer, end ofNo, you can't take a distribution circuit (submain) from a final circuit.
Discuss Spur off 32a house socket form garage for 20a supply. in the UK Electrical Forum area at ElectriciansForums.net
nothing else to say, this is the answer, end ofNo, you can't take a distribution circuit (submain) from a final circuit.
Note that this refers to permanently connected equipment (for which the load would be known and fixed). This would not allow for connecting socket outlets or another consumer unit, for which the load is obviously not known nor fixed.The IET doesn't seem to agree with that sentiment, and suggest connecting equipment via a 16A breaker in the OSG. This is from appendix H, P211:
Permanently connected equipment should be locally protected by a fuse complying with BS 1362 of rating not exceeding 13 A or by a circuit-breaker of rating not exceeding 16 A and should be controlled by a switch, where needed (see Appendix J).
@westward10 asked him to clarify as to what he was actually wanting my answer was in response to the Ops post hence is why I quoted the Ops post in my one with yes he can.The OP asked if he was "allowed" to take use 16A or 20A protection from an unspecified device to give himself an extra 3kW on a garage supply. The OP stated that their intention was to do so by "spurring" this unspecified protective device off a ring final circuit in place of a fcu. Her went on to clarify that this would supply 16A & 6A RCBOs in the garage.
You responded by stating that "he could".
These are the facts and let's not dress it up by claiming any information beyond that posted.
The advice wasn't in line with regulatory requirements and has the potential for loads considerably above that permitted to be carried by the cable intended for use if 20A protection is used at the proposed 'spur'.
Edit: I'm not the forum police and you're free to post as you please. On this occasion I believe the advice to be inappropriate and challenged it.
The max load of the entire circuit is still governed by the 32amp breaker.Note that this refers to permanently connected equipment (for which the load would be known and fixed). This would not allow for connecting socket outlets or another consumer unit, for which the load is obviously not known nor fixed.
Of course, this appendix is dealing with standard (formerly known as conventional) final circuits.
There is nothing to stop a competent designer from doing whatever they want, as long they note it as a deviation on the certification, and declare that it is no less safe than it would be if the design was done strictly to BS7671.
@westward10 asked him to clarify as to what he was actually wanting my answer was in response to the Ops post hence is why I quoted the Ops post in my one with yes he can.
Governed to what level of overcurrent?The max load of the entire circuit is still governed by the 32amp breaker.
How different would it be if the ring was extended, which I assume you would agree was ok ?Governed to what level of overcurrent?
A downstream type B 20A mcb could allow more than 32A for a considerable period of time on the proposed spur, without tripping. Not sure 32A protection at source is going to do much.
It refers to permanently connected equipment, not specifically permanently connected current-using equipment.Note that this refers to permanently connected equipment (for which the load would be known and fixed). This would not allow for connecting socket outlets or another consumer unit, for which the load is obviously not known nor fixed.
Of course, this appendix is dealing with standard (formerly known as conventional) final circuits.
There is nothing to stop a competent designer from doing whatever they want, as long they note it as a deviation on the certification, and declare that it is no less safe than it would be if the design was done strictly to BS7671.
Again that's not in line with OP's proposal of 16A or 20A protection.How different would it be if the ring was extended, which I assume you would agree was ok ?
A double socket outlet could have a 26 amp load, but one that has 16amp load would be too much ?
Reply to Spur off 32a house socket form garage for 20a supply. in the UK Electrical Forum area at ElectriciansForums.net
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