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115 volts for a 230 volt circuit, 138 volts on a 277 volt circuit.

Yes, but 115 volts for 5 seconds violates the IEC's body graph.

BS7671, Table 41.1. :)

Why do circuits 32 amps and under require a 0.4 second disconnection time at 230 volts, but circuits over 32 amps are legally allowed 5 seconds? 115 volts for 5 seconds is enough to cause injury to the body.

Thank you, will check it out.

Ie, NEC forbidding:

Can anyone tell me if the neutral is distributed aboard ships and if it is earthed?

Ok, say you had a building that needed backup power. Do any British Regs require that the loads be subdivided onto different branches and different automatic transfer switches based on type and priority?  

Ok, I don't thank folks are understanding. There are no line to neutral loads, so there is no PEN or TN-C. It is TN-S without the neutral distributed.  But for some reason the regs want a none current carry conductor to be treated as it would be carrying current. I'd like to earth at both...

It won't, not with everything connected line-line. Perhaps PE would be a better term.

Ok, but why require that the neutral be isolated from earth when it does not carry any load?

I want the neutral earthed in all 3 places, at source 1, source 2 and at the main gear.  Nothing gained by isolating it.

Correct- two sources- but the foot notes say neither can be earthed. Only in the main gear and beyond.

Why is earthing of the neutral forbidden at the supply transformers in a 3 phase 3 wire system? This has me beyond words confused. 

But you have time as well.

I know, but nothing says that subjecting a person at 500 ohms body resistance to 75 volts for 0.8 seconds causes dangerous physiological responses. Thanks :)

How much does code limit voltage drop? I'm confused, where does this say 75 volts for 0.8 seconds at a tpyical body impedance results in burns or ventricular fibrillation? 

Yes But also remember I'm dealing with 138/240Y, and not 230/400Y. The voltage to remote earth is way lower. 

Thats why I'm referencing the IEC's body graph and asking here. 0.8 to 0.4 is a big jump. I know the IEC us using a voltage divider, and that the nominal voltage can be +10%. However, 0.8 seconds for a 120 volt Uo and 0.4 seconds for a 138 volt Uo is a big jump. Why not 0.75 or 0.6 at...

Yes, but remember that it means more copper. Having to run 4mm2 where 2.5mm2 will do is a big incentive to use a longer disconnect time.