SDS EGC larger than ungounded conductor?

[Twoskinsoneman]

Is this possible? Here was my thought process when I was just reading through some old posts for fun gaining knowledge. One post read about sizing generator conductors.
Let's say single phase gen SDS (neutral of gen connected to ground run 4-wire)
All NEC 05
445.13 It shall be permitted to size the neutral conductors in accordance with 220.61.
220.61 The feeder or service neutral load shall be the maximum unbalance of the load determined bythis article (in this theoretical case lets assume 99% of loads are 2 phase 240 loads no neutral...very low low unbalanced load)
now of SDS systems 250.30 (A) (2)says

Equipment Bonding Jumper Size
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Where a bonding jumper of the wire type is run with the derived phase conductors from the source of a separately derived system to the first disconnecting means, it shall be sized in accordance with 250.102(C), based on the size of the derived phase conductors.

It seems to me that this Equipment bonding jumper is going to have to be a lot larger than the ungrounded conductor.

Does anyone see anything wrong with this thinking?​

 

[crossman]

It seems to me that this Equipment bonding jumper is going to have to be a lot larger than the ungrounded conductor.

Does anyone see anything wrong with this thinking?​

You meant to say "grounded" up there in the bold, right?

Is this a generator in conjunction with a utility fed srevice? There could be some issues based on where the main bonding jumper / system bonding jumpers are installed. Can you give more details? Does the transfer switch have a solid neutral connection between service and generator? Or is the neutral switched?

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[crossman]

See 250.30(A)(8)(a)

Essentially, if the grounded conductor will be used also as a path for fault current between the generator and the premises, then it must be sized by 250.66 and 12.5% if off the table. This would be the case if the transfer switch does not switch the neutral and/or if the generator does not have a main/system bonding jumper installed.

If the transfer switch switches the neutral and/or if the gen does have a main/system bonding jumper, then it is okay for the neutral to be smaller than the equipment grounding conductor. This is because the neutral would not be used a a path for fault current.