Am I in the privvy of the tap rule?

[al in wi]

Background:
Weird (grandfathered) installation has a building with 2 incoming utility services. Call it Utility A (UA) and Utility B (UB). There is no tie between services. They are serving 2 separate areas of the building, each approximately 400kW. The project requires a generator to back up whole house in case of outage. So instead of one generator of 1MW, we go with 2 x 500kW generators, G1 and G2. One for each utility. At first, I was going to have a group mounted cb's in switchboard, to "take in" power from generator after paralleling, and then "feed" the transfer switches.

An idea came up to instead use 2 breakers for each generator, key interlocked for manual operation, so that G2 can be used to serve UA (which was the utility side being primarily served by G1) in case G1 fails or is under maintenance.

Question:
As a value engineering idea, can the switchboard really be removed and instead use TAP rule with a wireway above the transfer switches containing the tap lugs?
The thought is that this will remove the switchboard and the paralleling/synching operation of the generators and it will be less costly than original design of traditional multiple generators paralleling into a switchboard with multiple feeders to multiple ATS.

 

[Little Bill]

Bump

 

[synchro]

Another approach that would avoid paralleling of generators would be to insert two manual transfer switches (MTS's) between the ATS's and the generators. One MTS would connect the left two ATS's (DP1 and LS) to either G1 or G2, and the other MTS would connect the right ATS (DP2) to either G1 or G2.

 

[al in wi]

Another approach that would avoid paralleling of generators would be to insert two manual transfer switches (MTS's) between the ATS's and the generators. One MTS would connect the left two ATS's (DP1 and LS) to either G1 or G2, and the other MTS would connect the right ATS (DP2) to either G1 or G2.

True. We actually have that laid out too. But then the added cost of MTS's is close to the deducted cost of the switchboard, especially after installation. What we are chasing is a VE idea that is worth enough $$ that the client is ok with loss of some automatic function.

IE...the question was: "If I, the user, can manually just load shed and switch over the gensets, can we get rid of the switchboard and just use an operational procedure to switch genset uses?"

The answer maybe: "Yes, but there is no significant dollar saved and you lose a function. So, yes...bet it is not worth it"