Service change 240 Open Delta to 208 Y system

[blingbling4r]

I am trying to estimate a job due later today and I'm trying to get my bearings straight on this issue.

We are changing a service from 240 Open Delta to 208 Y system. What electrical requirements should I be aware of during the change? More specifically would various loads in the building be affected (i.e. HVAC, EVAP, air compressors, water pumps, etc)? I thought that most of those loads are rated at 200-ish volts so a 208Y system would suffice something that runs at 240V.

I'm worried that I may need to put in a delta transformer to supply those loads. I haven't had to do something like this before so any input would be greatly appreciated.

 

[wirenut1980]

Funny...

Funny...

:smile:I work for a utility and have a customer that may have to do the exact same thing, since we do not provide "new" delta services anymore. Check motor nameplates for voltage ratings. A 240 V or 230 V nameplate rated motor will not work very well with a 208 V supply. Hopefully the motors have a 208-230 V rating. If not, then you will either have to replace motors with proper voltage rating or install a transformer to boost from 208 V to 240 V.

 

[al hildenbrand]

I agree, the nameplates of the motors at the site are the only way to tell which have to get special treatment. Hope you can find them all.

 

[iwire]

This may help match up motor and equipment requirements with acceptable service voltages.

 

[Rick Christopherson]

One thing that a lot of people don't think about, is that with the smaller dual voltage (120/240) single phase motors, you are better off reconfiguring them for 120 volts when you have a 120/208 system.

 

[LarryFine]

One more thing: Many of the open Deltas we see around here, being located mostly in older areas, pre-date 208v-rated equipment, so beware of the equipment ratings as advised above. Don't presume 240v equipment will operate on 208v unless so advised by the manufacturer.


Oh, and welcome to the forum!