Conductor overcurrent protection.

[arnettda]

445-13 for generator conductors they must be rated 100% Does this mean they have to fused at there rated 310-16 value? And for parrel conductors if 2 500mcm conductors 75degC rated at 380 amps x2 would give me 760 amps, can I fuse this at 800 amps or do I need to go to three 300 MCM. 3x285 amps=855 amps. Thanks

 

[augie47]

445-13 for generator conductors they must be rated 100% Does this mean they have to fused at there rated 310-16 value?

Note that (a) the basic rule is 115% and (b) this is from the generator to the 1st distribution device which is normally at the generator

And for parrel conductors if 2 500mcm conductors 75degC rated at 380 amps x2 would give me 760 amps, can I fuse this at 800 amps or do I need to go to three 300 MCM. 3x285 amps=855 amps. Thanks

Parallel 500kcmil in separate conduits would normally be adequate for 760 amps in calculated load and could be protected by an 800 amp OCP if the 760 amp is not exceeded.

 

[arnettda]

Note that (a) the basic rule is 115% and (b) this is from the generator to the 1st distribution device which is normally at the generator


Parallel 500kcmil in separate conduits would normally be adequate for 760 amps in calculated load and could be protected by an 800 amp OCP if the 760 amp is not exceeded.

Where does this say this in the code? I am unable to find it.

 

[jumper]

where does this say this in the code? I am unable to find it.

240.4(b) .......

 

[raider1]

Where does this say this in the code? I am unable to find it.

Which part?

For the sizing of conductors for a generator take a look at 445.13 and it will give you the 115% requirement.

Also take a look at 240.4(B) for the next size up rule for overcurrent devices.

Chris