Q & A of the Day - Does a sub-main have to have an isolator at the origin?

BookmarkThis 17.08.2009
SELECT
 

Our Voltimum Experts answer your questions on a daily basis in our Technical Expertise area. This one, concerning domestic sub-main topics, is answered by SELECT:

Question: I have a couple of sub-main questions:

1) Does a sub-main have to have an isolator at the origin, ie - where it leaves the consumer unit or distribution board?

2) Could it still be classed as a sub-main if it comes off a spare circuit breaker - say 63A - in domestic consumer unit?

Answer: A sub-main is now termed a distribution circuit and:

1) If it is more than 3m in length, the cable should be provided with overload protection.

2) If the cable is protected in a consumer unit, it would normally be classed as a circuit.

To see many more Q & A in Voltimum UK's Experts Area, please click on the link:

www.voltimum.co.uk/consult.php?universe=consult.index.questions

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SELECT
The Walled Garden, Bush Estate,
Midlothian, Scotland EH26 0SB
Tel: 0131 445 5577
Fax: 0131 445 5548
Email: admin@select.org.uk
Web: www.select.org.uk
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Source: SELECT & James Hunt

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