How to get 120/240V Single Phase

[goodoboy]

Then your choices are a 480V to 240V single phase transformer or feed your panel from one of your 208V panels and buck/boost for the a/c.

Is this some kind of special a/c unit?

Thank you ActionDave,

What does "feed your panel from one of your 208V panels and buck/boost for the a/c. " ?

Thanks

 

[goodoboy]

If the A/C unit is only rated for 240 and this is new and was specified by the A/C contractor then he needs to haul the unit back and get the correct one. The plant should not have to jump through hoops and install special things because the A/C contractor did not do his homework.

That is IMHO

Thanks Sierrasparky,

Its my fault because I approved the vendor panel for 120/240V, so I approved the 240V A/C unit for the building I need to power up.

Thanks

 

[Smart $]

Thanks Sierrasparky,

Its my fault because I approved the vendor panel for 120/240V, so I approved the 240V A/C unit for the building I need to power up.

Thanks

Though it could, in the end it may not matter...

Also, is the A/C equipment 1Ø or 3Ø?

The first question when adding to an existing system is always whether it is capable. Until you answer that question with certainty and amount, all other preparations are moot. For example, your 208/120 system may not be capable while your 480V system is.... and you are left converting anyway. The main difference is going to be how the system is balanced now and how it will be balanced after the addition.

 

[ggunn]

Thanks Sierrasparky,

Its my fault because I approved the vendor panel for 120/240V, so I approved the 240V A/C unit for the building I need to power up.

Thanks

Where is that "UNDO" button? If construction has not started yet can't you fall back and regroup?

 

[ActionDave]

Thank you ActionDave,

What does "feed your panel from one of your 208V panels and buck/boost for the a/c. " ?

Thanks

If you are able to feed your new panel from an existing 208V panel you can install a buck/boost transformer on the circuit to the A/C to get your 240V instead of buying a 480V to 240V transformer. I wouldn't but it is an option.

I still think the A/C will work on 208V.

 

[goodoboy]

Though it could, in the end it may not matter...

Also, is the A/C equipment 1Ø or 3Ø?

The first question when adding to an existing system is always whether it is capable. Until you answer that question with certainty and amount, all other preparations are moot. For example, your 208/120 system may not be capable while your 480V system is.... and you are left converting anyway. The main difference is going to be how the system is balanced now and how it will be balanced after the addition.

Thank you for response.

The A/C unit is 1 phase.

How do I confirm if existing system is capable?

Thanks,

 

[goodoboy]

If you are able to feed your new panel from an existing 208V panel you can install a buck/boost transformer on the circuit to the A/C to get your 240V instead of buying a 480V to 240V transformer. I wouldn't but it is an option.

I still think the A/C will work on 208V.

Thank you,

Is there somewhere in the NEC where 208V is allowed when the load requires 240V?

Thank you

 

[goodoboy]

Thanks all for the reply.

I know my questions are basic, just trying to understand.

 

[ActionDave]

Thank you,

Is there somewhere in the NEC where 208V is allowed when the load requires 240V?

Thank you

NEC only cares about the wiring up to the point where you hook up your stuff.

Most motors and A/C equipment will have 240V and 208V listed on the nameplate. Few will be 240V only.

 

[Smart $]

How do I confirm if existing system is capable?

Well there is no easy way to do what is required, which is an Article 220 load calculation for the service and any subpanel feeders in the path. Once you know the calculated load, you can verify wire ampacities and ocpd ratings are good for both existing and existing plus anticipated. See especially 220.87.

Considerations for any intermediate transformers' capacity will also be required. Should be good if service and feeders are okay but if you go to this degree, you may as well verify transformers in the process.

 

[goodoboy]

Thank you so much to all that has helped me.

I was approved to purchase transformer. I will start new thread on proper way to size it.

Thank you kindly.

 

[greg4230]

check the single 240v load and see if it has a multi tap xfmr in it. If it does you can just change the taps in it.