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#136942 - 05/13/03 09:35 AM REFERENCE METHODS
james S Offline
Member
Registered: 05/13/03
Posts: 107
Loc: West England
WHAT REFERENCE METHOD IS USED IF YOUR METHOD IS NOT LISTED IN THE CURRENT CARRYING CAPACITY TABLES EG CABLES BURIED DIRECT UNDERGROUND ( WITH MECHANICAL PROTECTION OF COURSE).I CANT EVEN FIND IT IN THE MAIN REFERENCE METHOD TABLES!

WORKING IN ACCORDANCE WITH THE IEE REGULATIONS.


[This message has been edited by james S (edited 05-13-2003).]
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#136943 - 05/13/03 10:21 AM Re: REFERENCE METHODS
Bill Addiss Offline
Member
Registered: 10/07/00
Posts: 3875
Loc: NY, USA
James,

Welcome to ECN,
Is this a question about UK Regs? or US?

Bill

[This message has been edited by Bill Addiss (edited 05-13-2003).]
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#136944 - 05/13/03 10:43 AM Re: REFERENCE METHODS
james S Offline
Member
Registered: 05/13/03
Posts: 107
Loc: West England
UK
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#136945 - 05/13/03 11:59 AM Re: REFERENCE METHODS
sanUK Offline
Member
Registered: 01/09/03
Posts: 45
Loc: Scotland
There is no reference method for Cables buried underground, only in Enclosed trenches.

Most likley because there would not be any problems with heat dissipation under the ground, so no derating.

522-06-03 details requirements for a buried cable or conduit.
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#136946 - 05/13/03 04:39 PM Re: REFERENCE METHODS
C-H Offline
Member
Registered: 09/17/02
Posts: 1497
Loc: Stockholm, Sweden
The current carrying capacity of a cable buried directly is very high, in fact higher than cables clipped directly. The limit is likely to be when the cable it leaves the ground.

I don't have a UK reference, but I could try to dig up a Swedish reference. Or the some of our American friends could tell us what the NEC or CEC has to say.

Edit: I took the first reference that popped up. Swedish AXBJ, 5 conductor, aluminium 1kV cable.
Conductor 65°, air 25°C,
ground 15°C, depth 0,7 metres

Gauge.......50 95 150 240 sq.mm
In ground...160 230 295 385 Amps
In air......140 210 275 370 Amps

Just to give an example.

[This message has been edited by C-H (edited 05-13-2003).]
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#136947 - 05/27/03 03:51 PM Re: REFERENCE METHODS
lyledunn Offline
Member
Registered: 06/30/02
Posts: 159
Loc: N.Ireland
Interesting point. I use AMTECH cable calculation programme. It states reference method 7 for your particular situation. Now I left my glasses at the caravan this weekend but I cant see ref method 7 in appendix 4. In any event I would be glad to calculate any circuit for you using the programme.
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lyle dunn
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#136948 - 05/30/03 04:52 PM Re: REFERENCE METHODS
james S Offline
Member
Registered: 05/13/03
Posts: 107
Loc: West England
Thanks, much appreciated all!

[This message has been edited by james S (edited 05-30-2003).]
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#136949 - 06/07/03 01:45 AM Re: REFERENCE METHODS
Trumpy Offline


Member
Registered: 07/05/02
Posts: 8211
Loc: SI,New Zealand
Just wondering,
What is a reference method?.
Is this like a Current carrying capacity Table, in various types of installations?.
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#136950 - 06/07/03 06:05 PM Re: REFERENCE METHODS
sanUK Offline
Member
Registered: 01/09/03
Posts: 45
Loc: Scotland
Quote:
Just wondering,
What is a reference method?.
Is this like a Current carrying capacity Table, in various types of installations?.


Yes you look up the Schedule of installation methods table first (4A1), to get the Method No, then refer the method Number to the current carrying capacity tables, also taking into account various correction factors.
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