Oh ok, I misunderstood, thought it was just for connecting/disconnecting as the work was being done and switched over.
Well like TJ said looks to be a more expensive option.
Yes, regardless of which option you go, you're forcing yourself to purchase (2) 1200A breakers and a good bit of extra bussing. I typically see service shutdown time as relatively minimal. Sometimes it can be done in less than a day and during off hours.
I'll consider it. Not sure why the 4-pole MTS.
You're right. It's only needed if the genset is a separately derived system, which a roll-up likely isn't.
I appreciate all the comments. There are options I have not considered.
Its to minimize potential nuisance tripping of the gfpe
The problem i am seeing is the GFPE which you cant do with a standard safety switch. Without fuses, you will have a low SCCR. with fuses you need GFPE.
The GFPE is on the MCB in panel 'P1".
Hmmm, I believe it would be required at the first device
I am beginning to think I may need to make the MTS with OCP. We where planning on NF.
That is not always the case. And it depends on what you mean by "low".
It would be 10k for a "standard" NF switch. That is probably not enough for the OP's service, but you never know .
Available fault for a 1200A 480V service is likely not going to exceed 50k, can be verified with the POCO. Rule of thumb for myself is that a service entrance at 480V is given a 65k rating and reduced upon receipt of the available fault, because POCOs can be extremely slow. I'll bump up to 100k once I get above 2500A. 10k will 100% not be enough for this service unless this is extremely remote or the service disconnect is a significant distance away from the transformer. I just did a 2000A 480V service with an available fault of 48ka.
A pringle switch with a shunt trip coil wired to a GFP relay is the way to do it if fuses are desired. Digitrip breakers of these size are rated at 65ka or 100ka. https://breakeroutlet.com/circuit-b...e-d-1200-amp-micrologic-lsig-circuit-breaker/
Regardless of the code, this would mean that if any maintenance is required inside the MTS, you would need the utility to come shut off the power unless someone wants to work on live 480v, which is a death wish at this amperage in my opinion. Also, in the event of a fire inside the MTS, the only protection and means of disconnect would be the utility fuses. Most Fire Marshals will not allow this.
Yes, but if the roll up generator is not bonded, having a 4-pole MTS would mean you don't have a bond when switched. I would just want to make sure the roll up is bonded. I'm ignorant on if generators of this size typically have an internal NG bond.
Not to my knowledge