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#178705 - 06/09/08 07:17 PM 5% rule.
Sandro Offline

Registered: 12/30/01
Posts: 449
Loc: Stoney Creek, ON, Canada
300 mcm T90Nylon is rated for 295amps. Using the 5% rule, one could use parallel 300mcm runs for a 600 amp service?

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#178706 - 06/09/08 08:22 PM Re: 5% rule. [Re: Sandro]
twh Offline

Registered: 03/11/04
Posts: 895
Loc: Regina, Sask.
If your calculated demand is 620 amps, you can put in a 590 amp service, which would be fused at 600 amps according to 14-104, if a 590 amp fuse is not available. That is, you can install a 590 amp service and fuse it at 600 amps.

#178920 - 06/15/08 07:32 PM Re: 5% rule. [Re: twh]
ThorahSparky Offline
Junior Member

Registered: 04/13/03
Posts: 13
Loc: Orillia,ON,Canada
Generally if you are considering applying the 5% rule I would first run it by your local inspector. Yes, it is a rule but doing so makes for a better relationship, especially if you don't know him/her.


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