Generator start wiring 1

[av132]

In the standby system with multiple ATS's shall the generator start wiring from each ATS run directly to generator as homeruns or I can connect several ATS's wiring and run it just as single homerun?
Is it a Code issue or just good practice?
Thanks in advance.

 

[rbulsara]

Code requirements are meant just for safety. Code does not care if your system works or not, or whether it is a good design.

So the real question is do you want to be a good engineer or a bad one? Can you (or not) understand the pros and cons of the two approaches? Do you really want one broken wire take down entire facility?

Make your own decision.

 

[davidbeach]

What rbulsara said.

 

[VTer]

Well I know that david and rbulsara have much much more experience than me, but I think that you should be able to connect several ATS’s together but instead on having one home run (one set of wires), I would suggest using two homeruns (two sets of wires) for the reasons rbulsara stated. I do not see a reason why every ATS should have its own home run. Connect the ATS’s in parallel and bring another set of wires/homerun isolated from the first “homerun”(separate conduit) to each ATS contact so incase one fails because of “broken” wire there is a backup. I have attached a very basic sketch of this. See if it’s applicable in your case, and if it makes any sense in doing this. You may have to rotate the pdf.

"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla

 

[EmergencyPowered]

The real question here is whether the ATS's have any additional wiring. Position indicators (ACC 14A & 14B) contacts, load add/load (ACC 30B) shed wiring or any elevator interface (ACC 31M,F, etc). If so a "home run" from each ATS to the Engine Generator Controls and/or Elevator controls would be necessary, so an additional few wires would not be any additional cost. For simple engine start (ACC 7) it is very common to "daisy chain" the start wires. In the event of a false engine start problem, the daisy chain makes it much harder to troubleshoot, as the closed contact ohm reading would be present on all ATS's.

 

[waross]

I would decide this on an individual basis. You can discuss probabilities indefinitely, and what is good in one installation may be a disaster with another layout. I have found it to be a good idea to run controls in the same route as the power wiring. Too many times I have gone out to trouble shoot an installation and found the control wiring disappearing into the woodwork. I have on occasion found it much quicker and easier to abandon control wiring and re run it rather than try to follow it. If it follows the power wiring, you can usually follow it.
But there are always exceptions.

Bill
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"Why not the best?"
Jimmy Carter