Elevartor Service

[callmestu]

This thread was moved to its own from another slightly related thread:::::::

Hey Guys,
Two things... I was a Journeyman Contractor for four year from 1989 to 1992. The wonderful Commonwealth of Taxachusetts (yes, I am a Masshole) allows Journeymen Electricians to start a business with four important (but not worth mentioning here) restrictions.

My second point is that I am designing an electrical service for a 12 unit condo building and I will have a 120/240 volt single phase, 3 wire service for the dwelling units and most of the house loads. The question comes from the 240 volt delta 3 phase, 3 wire electrical service for the elevator. The reason I found this post if because I believe that my elevator will be 40HP and I believe it will be the only thing on that service.

My question is: What size service do I need to provide? I am expecting between 104 and 120 amps for the elevator, depending on the service factor. My calculations tell me that I should have a 250 volt breaker protecting that motor. Does that mean I need a 250 amp (minimum) service?

[btw: Masshole has officially been added to the Oxford English Dictionary]

 

[petersonra]

Hey Guys,
Two things... I was a Journeyman Contractor for four year from 1989 to 1992. The wonderful Commonwealth of Taxachusetts (yes, I am a Masshole) allows Journeymen Electricians to start a business with four important (but not worth mentioning here) restrictions.

My second point is that I am designing an electrical service for a 12 unit condo building and I will have a 120/240 volt single phase, 3 wire service for the dwelling units and most of the house loads. The question comes from the 240 volt delta 3 phase, 3 wire electrical service for the elevator. The reason I found this post if because I believe that my elevator will be 40HP and I believe it will be the only thing on that service.

My question is: What size service do I need to provide? I am expecting between 104 and 120 amps for the elevator, depending on the service factor. My calculations tell me that I should have a 250 volt breaker protecting that motor. Does that mean I need a 250 amp (minimum) service?

[btw: Masshole has officially been added to the Oxford English Dictionary]

a 240V 40 HP 3 phase motor is 104 FLA according to the charts. You can go up to 250% (rounded up to the next standard rating) of that if you use a CB.

I don't see how the breaker rating has any bearing on the service size. You have to calculate the service size according to the rules in article 220. My guess is you will get whatever the POCO supplies as a minimum size 240V 3 phase service.

 

[callmestu]

The question was because the elevator was the only thing on the service. Even with the 220 calcs it would still be less than 200 amps for my total load and more than 200 amps for my recommended breaker protection.

 

[petersonra]

The question was because the elevator was the only thing on the service. Even with the 220 calcs it would still be less than 200 amps for my total load and more than 200 amps for my recommended breaker protection.

it does not matter how many things are on the service. you still have to use the procedure in article 220 to calculate the service size, and the rating of the CB on the motor circuit does not enter into that calculation.

you can make the breaker smaller if you want. It just cannot be larger than 250% rounded up to the next standard rating.

if you are asking about using the motor OCPD as the service OCPD, take a look at 230.90. especially exception 1.

 

[augie47]

................................
if you are asking about using the motor OCPD as the service OCPD, take a look at 230.90. especially exception 1.

To me, that is the "key". Base your conductor and breaker size on Art 430.
(Be prepared to explain the calculations )

 

[callmestu]

Thank you very much and I apologize for hijacking the other post.

 

[callmestu]

That's the same as putting #10's on a 40 A breaker for an ac unit.
I should have thought of that.
Thanks again.

 

[Barbqranch]

Doesn't the elevator company specify the size of the breaker?

 

[iwire]

My second point is that I am designing an electrical service for a 12 unit condo building and I will have a 120/240 volt single phase, 3 wire service for the dwelling units and most of the house loads. The question comes from the 240 volt delta 3 phase, 3 wire electrical service for the elevator.

Hello fellow taxpayer.

What makes you believe you are going to get a 120/240 single phase service and a 240 delta service to this building?

Been working in the Boston/Providence area for many years and have not seen a new installation like that happen.

I would expect to get a single 3 phase 208Y/120 volt service from the power company. That single service would supply a three phase four wire house panel and twelve single phase 208/120 apartment panels.

 

[callmestu]

Hello fellow taxpayer,
The service is in South Boston.
I got the info directly from the horse's mouth; Ron Bonigli of Eversource. He is an actual engineer, not just a CS rep.
That's all they have available in the street unless the owner wants to pay big $$$$$ to bring 3 phase down the street from wherever it is.

Yes, the elevator company specifies the breaker size but since the elevator is the only thing on the service... 230.90 exception 1 works for me.

Thanks Guys.
Have a great weekend!!!