Hotel Service and sub panel Question

[shanebdx]

I am installing a 1600 amp 120/208 3 phase 4 wire main distribution panel in a hotel. The engineer speced out all the sub panels to be 120/240. There isnt any equipment that is 208 volts in the building. So why do they want a 120/208 3 phase main???

 

[wireguru]

I am installing a 1600 amp 120/208 3 phase 4 wire main distribution panel in a hotel. The engineer speced out all the sub panels to be 120/240. There isnt any equipment that is 208 volts in the building. So why do they want a 120/208 3 phase main???

probably all the poco will give him at that size

 

[mdshunk]

probably all the poco will give him at that size

Right. They probably don't WANT a 120/208 service. That's probably all they can get. Having said that, I have no idea why a hotel would WANT 120/240 subpanels. Seems like a waste of a transformer. I wouldn't think they'd have any critical equipment that couldn't also run on (or be spec'd for) 208.

 

[peter d]

Right. They probably don't WANT a 120/208 service. That's probably all they can get.

Ya, for that size 120/240 is not available round yonder.

 

[480sparky]

Makes me wonder if someone got a deal on PTAC units that are labeled at 240v only.

 

[mdshunk]

Makes me wonder if someone got a deal on PTAC units that are labeled at 240v only.

You can buy a heck of a lot of PTAC's for the price of a big transformer.

 

[mdshunk]

Ya, for that size 120/240 is not available round yonder.

Sprechen zie Deutsch?

 

[wireguru]

by 120/240 panel, are we talking about a 120/240 panel, or a 120/208 single phase panel? This is a big difference to clarify.

If you have 240vac only loads (because someone got a deal on some airconditioners) seems like it would be most cost effective to have 120/208 3ph panels for the 120v loads, then use 208-240 delta/delta transformer with 240v delta panels for the 240 loads...smaller transformer(s) and keeps everything balanced. Maybe someone who is more knowledgable about this can chime in....

 

[480sparky]

You can buy a heck of a lot of PTAC's for the price of a big transformer.

Yeah, but 1600a for a hotel means there's probably a couple hundred rooms.

 

[peter d]

Sprechen zie Deutsch?

Nein.

Yo hablo espanol un poco.

 

[mdshunk]

Yeah, but 1600a for a hotel means there's probably a couple hundred rooms.

I guess.

I wonder if they just aren't going to use regular single phase panels marked 120/240, but feed them at 120/208?

 

[480sparky]

I guess.

I wonder if they just aren't going to use regular single phase panels marked 120/240, but feed them at 120/208?

Possible. But what to do with that extra 32 volts......:grin:

 

[shanebdx]

By having a 3 phase 4 wire MDP and all 120 /240 subs, will the loads be distributed at the MDP without overloading?

 

[shanebdx]

Three story 61 rooms

 

[peter d]

Possible. But what to do with that extra 32 volts......:grin:

That's easy. The maids have to go around with their voltage collection buckets every day and clean up the floors of the electric room. How could you not know that? :roll:

 

[mdshunk]

Possible. But what to do with that extra 32 volts......:grin:

Charge the emergency light batteries.

 

[480sparky]

That's easy. The maids have to go around with their voltage collection buckets every day and clean up the floors of the electric room. How could you not know that? :roll:

But how do you keep that 32 volts in the receptacles from leaking all over the building?

 

[peter d]

But how do you keep that 32 volts in the receptacles from leaking all over the building?

Use a tamper resistant receptacle.

 

[wireguru]

But how do you keep that 32 volts in the receptacles from leaking all over the building?

the shutters in the TR receps keep it from coming out the front, and the AFCIs keep if from coming out the back.

 

[wireguru]

Use a tamper resistant receptacle.

darnit i was typing that