British Standards versus NEC

[BECREZ]

I am reviewing an existing installation in the U.K. Presently there is a 1000 amp feed to an MCC. Prior to entering the feeder breaker of the MCC, there is a cable tapped off the feeder and services a 160 amp breaker which in turn acts as a main to a distribution panel. The tap is sized for the ampacity of the 160 amp service. In the NEC world this would qualify under the 25 foot tap rule. Does anyone know if there is a "tap" rule in the British Standards similar to that in the NEC?
Any assistance would be appreciated.

 

[mpparent]

For the NEC, it really depends on the length of tap. How long is the tap?

Mike

 

[BECREZ]

I realize that the length of the tap is a qualifier in the NEC, my question was if this same type of tap rule exists in the British WIring Regulations. Nonetheless the tap in question is around 25 feet.

 

[mpparent]

Sorry,

I mis-read your post.

Mike

 

[richard1st]

Becrez,

If you are working in UK, suggest you get a copy of IEE Wiring Regulations (BS 7671) ISBN 0 85296 988 0 available from sales@iee.org.uk.

Regulation 473-02-02 says that
'The ... protective device may be placed ... at a point on the load side [such that the distance shall]:
i) not exceed 3m in length, and
ii) ... reduce to a minimum the risk of fault ...
iii) ... reduce to a minimum the risk of fire ...

Cutting through the bull, my interpretation is that this is like your NFPA70 para 240-21b for the 10ft length ONLY. There is no general provision for taps of 25ft and above in the same way that NFPA 70 does.

Hope this helps,
RAC.