415/240 WYE

Status
Not open for further replies.
A

abrace

Member
Location
New Hampshire
Occupation
Telecommunications Engineering
Got a site with a bunch of IT equipment (servers, routers, etc). Site is currently 208 wye. Considering an upgrade.

Most of the IT gear is currently 2-pole 208V 60A circuits uconnecting to large power strips. 415/240 would allow for 1 pole per circuit, saving a bunch of panel space not to mention bringing an addition 2kw per circuit, which would facilitate connecting an additional server per circuit.

Eaton makes a nice large 415V UPS, so that isn't a problem. I assume we should approach the PoCo and ask for a 480/277 service and then frontend the UPS with a transformer to get it down to 415/240, but wondering if anyone has actually done a 415 service and if that would make more sense?
 
The poco usually charges a premium if they agree to do it, as they have to keep a spare transformer in the yard. A sheet metal ductwork manufacture had a 120/240 delta service, they bought some Canadian equipment, and wanted 575 volts. Georgia Power gave them a ridiculously high price to build the bank. Put in a 75 kva transformer that easily powered what they had. That was about 25 years ago, and far as I know, they are still using it. Don’t remember what we quoted it at, but it was about a quarter of what the poco wanted, and their price didn’t include the service!
 
electrofelon said:
I have not had any luck getting a POCO to do a "non standard" service voltage. All the ones I deal with won't even do high legs anymore. Maybe there are some out there that are more flexible.
Click to expand...


None standard? You kidding? Billions of structures are served at 240/415Y.
 
abrace said:
Eaton makes a nice large 415V UPS, so that isn't a problem. I assume we should approach the PoCo and ask for a 480/277 service and then frontend the UPS with a transformer to get it down to 415/240, but wondering if anyone has actually done a 415 service and if that would make more sense?
Click to expand...

Certainly worth asking the POCO. They could build the bank with standard 240V transformers, so they might not be too fussed about the 'non-standard' voltage. Or as others have noted they might charge an arm and a leg and another leg for the service.

-Jon
 
I believe Eaton is the only manufacturer that sells a 416/240V native UPS that is UL listed and only in very specific sizes. Because of that, to make product bidding competitive, and to correspond to standard size utility transformers (if they are provided at low voltage) most data centers that I design are done at 480V, with a 480V UPS, then a step down transformer to address the UPS output at 416/240V to the racks. That way the generator pairing and HVAC equipment can be a normal 480V voltage as well. Most of the facilities I design are medium voltage services, so I can spec the transformer to any low voltage I want since the building owner, owns it.
Anything too unique elongates leadtime and makes operations and maintenance a headache down the road.
 
ron said:
I believe Eaton is the only manufacturer that sells a 416/240V native UPS that is UL listed and only in very specific sizes. Because of that, to make product bidding competitive, and to correspond to standard size utility transformers (if they are provided at low voltage) most data centers that I design are done at 480V, with a 480V UPS, then a step down transformer to address the UPS output at 416/240V to the racks. That way the generator pairing and HVAC equipment can be a normal 480V voltage as well.
Click to expand...

Interesting, I had assumed Liebert had one as well. If thats true, the fact that they don't says a lot.

Seems like a standard 480/277 service is the way to go, and then just to decide whether a 415 transformer goes in front of a 415ups, or if we go with a 480V ups and drop it down to 415 on the back side. Thanks for the feedback.
 
The problem you will run into is that for the most part, the inexpensive single pole breakers you are likely thinking of are NOT rated to be used on 240V 1 pole. Most small MCCBs are "slash rated", meaning rated 120/240V where the maximum voltage TO GROUND cannot exceed 120V. So to use a 415/240V system, you must use "fully rated" 1 pole 240V breakers, which will be the larger more expensive MCCBs anyway, and maybe more importantly, harder to get quickly if you have to replace one, because hardly anyone uses them. True, you can get more 240V circuits in a panel that way, but the panel will be bigger to start with.
 
Jraef said:
The problem you will run into is that for the most part, the inexpensive single pole breakers you are likely thinking of are NOT rated to be used on 240V 1 pole.
Click to expand...

Indeed. Not only do you have the issue of slash rating, but also you have the issue that any panelboard that could host a 240V breaker is only rated for 240V between any conductors within.

More than likely, you'll need 277/480V distribution equipment (panelboards, disconnects, breakers, etc) to use with a 240/415V system, assuming you get equipment built for the North American market. A 277/480V breaker should work with a 240/415V system with no issue. If there is special functionality to the breaker (AFCI, GFCI, shunt trip, electronic trip instead of thermomagnetic, etc), I recommend checking with the manufacturer first, to see if you can use it on lower voltages.
 
Carultch said:
More than likely, you'll need 277/480V distribution equipment (panelboards, disconnects, breakers, etc) to use with a 240/415V system, assuming you get equipment built for the North American market. A 277/480V breaker should work with a 240/415V system with no issue.
Click to expand...
Agreed.
 
Carultch said:
Indeed. Not only do you have the issue of slash rating, but also you have the issue that any panelboard that could host a 240V breaker is only rated for 240V between any conductors within.

More than likely, you'll need 277/480V distribution equipment (panelboards, disconnects, breakers, etc) to use with a 240/415V system, assuming you get equipment built for the North American market. A 277/480V breaker should work with a 240/415V system with no issue. If there is special functionality to the breaker (AFCI, GFCI, shunt trip, electronic trip instead of thermomagnetic, etc), I recommend checking with the manufacturer first, to see if you can use it on lower voltages.
Click to expand...
Yeah this is what we see here, You can't use 240 breakers if your more than 250V RMS L-L.
The breakers need to be rated for the L-L as well as L-G.

I think Brant has a interesting thread on there about dealing with a power company.
Local POCO can be real prickly pears however a good 'shcmoozer' or some local politics can work in your favor.
Say building that wanted 415/240 was bringing in quite a few local jobs to the US the microchip industry,
but the Korean corporation was worried about our non-standard US power.
Now the POCO issues would be considered red tape.
They would get their transformers plus a tax break.
Because same corporation could locate in Plilly where they will give you any kind of power you want.
Philly is the most 'can do' place I know of as far a POCO's go. Granted this was 20 years ago.
Call up PECO energy in Philly and ask for a '5 wire two phase' or a corner grounded 480 delta, or a 13.5 kv 25 hz service, they got whatever you want its fascinating.
 
tortuga said:
Yeah this is what we see here, You can't use 240 breakers if your more than 250V RMS L-L.
The breakers need to be rated for the L-L as well as L-G.

I think Brant has a interesting thread on there about dealing with a power company.
Local POCO can be real prickly pears however a good 'shcmoozer' or some local politics can work in your favor.
Say building that wanted 415/240 was bringing in quite a few local jobs to the US the microchip industry,
but the Korean corporation was worried about our non-standard US power.
Now the POCO issues would be considered red tape.
They would get their transformers plus a tax break.
Because same corporation could locate in Plilly where they will give you any kind of power you want.
Philly is the most 'can do' place I know of as far a POCO's go. Granted this was 20 years ago.
Call up PECO energy in Philly and ask for a '5 wire two phase' or a corner grounded 480 delta, or a 13.5 kv 25 hz service, they got whatever you want its fascinating.
Click to expand...
Wasn’t there a guy that hung out in Philly many years ago that flew kits in thunderstorms? LOL!
 
Jraef said:
The problem you will run into is that for the most part, the inexpensive single pole breakers you are likely thinking of are NOT rated to be used on 240V 1 pole. Most small MCCBs are "slash rated", meaning rated 120/240V where the maximum voltage TO GROUND cannot exceed 120V. So to use a 415/240V system, you must use "fully rated" 1 pole 240V breakers, which will be the larger more expensive MCCBs anyway, and maybe more importantly, harder to get quickly if you have to replace one, because hardly anyone uses them. True, you can get more 240V circuits in a panel that way, but the panel will be bigger to start with.
Click to expand...


Or just get a standard THHQL 22kaic breaker and de-rate to 10kaic. 65kaic TXQL to 30 kaic.

Most of the breaker designs sold here are dual rated when sold outside the US. Typical runs kocks down the fault current substantially relative to the main MDP.


1612341909899.png
 
mbrooke said:
Or just get a standard THHQL 22kaic breaker and de-rate to 10kaic. 65kaic TXQL to 30 kaic.

Most of the breaker designs sold here are dual rated when sold outside the US. Typical runs kocks down the fault current substantially relative to the main MDP.

Click to expand...
If this project was outside of North America, that would be a viable solution. But these breakers are not UL listed at 240V single pole, so cannot be used that way here.

But if the project was outside of North America, 415/240V would be the norm, not the exception and the question would not have needed to be asked at all...
 
Jraef said:
If this project was outside of North America, that would be a viable solution. But these breakers are not UL listed at 240V single pole, so cannot be used that way here.

But if the project was outside of North America, 415/240V would be the norm, not the exception and the question would not have needed to be asked at all...
Click to expand...
I dont know, if someone wanted to use these they could go 90.4 and make a good case for special permission.
They are made by a reputable company.
And if I were the AHJ on that one I'd look at 110.3(A) 110.9,110.10 all the requirements of part VII of 240, 240.83, 408.58 and if the breakers met that along with a letter/phone call from GE I'd approve them.
 
Status
Not open for further replies.
Top