Go Back  DoItYourself.com Community Forums > Electrical, AC & DC. Electronic Equipment and Computers > Electrical - AC & DC
Reload this Page >

200 amp constant load on 50 KVM transformer. Already blew up 2 25 KVA ones

200 amp constant load on 50 KVM transformer. Already blew up 2 25 KVA ones

Reply

  #1  
Old 12-01-14, 05:56 AM
Member
Thread Starter
Join Date: Dec 2014
Location: United States
Posts: 12
200 amp constant load on 50 KVM transformer. Already blew up 2 25 KVA ones

So I have a 200 amp constant load from a data center type of environment. I have 400 amp installed in one building and 200 amp in the other. Both are hooked to the same transformer and together pull 200 amp of constant load 24/7. Since the 200 amp brake is in my home there are other loads on the at times from cooking and water heater but 97% of the load is 120v. Well two of the power companies 25 KVA transformers already blew up and they finally upgraded me to a 50 KVA (The load chart was filled out when I had the 400 amp service installed so they where aware of my requirements). When the 25 KVA transformers blew I was running all my equipment on 240v but I have now converted it all to 120v after reading that 120v will put half the load onto the transformer. I did a calculation that says the 50 KVA transformer should be good for just over 400 amps of constant load at 120v and 200 amps of 240v, does this sound right to you? Am I going to pop another transformer? I am worried cause the power company is threatening to charge me a ton of money for the next one, even though they know what my service loads are and installed the 400 amp service a little over a year ago for me. They are treating me like a criminal or something and scarring the crap out of my family with their threats. I support my family with my home business that uses the power. So I have to risk blowing the transformer or shut it all down and let my family starve. Am I going to be ok? I cant afford the the thousands of dollars they will charge me if another transformer blows, and they already told me that if I dont pay they will shut off my power. Its -2 deg here tonight so I dont want my kids to freeze either.

Thanks in advance!
 
Sponsored Links
  #2  
Old 12-01-14, 06:14 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,588
Amps go up as voltage goes down. A 25 amp load at 120 volts becomes 12.5 amps at 240. I think you really need to have a professional come in to evaluate and also talk to the power company. You might be having issues with the type of load being placed on the system.
 
  #3  
Old 12-01-14, 06:29 AM
Member
Join Date: Nov 2012
Location: USA
Posts: 3,314
By changing things to 120 I would say you have made matters worse,that transformer should be a minimum of a 75 kva and at that would be roughly 300 amps ,maybe you should get in touch with the POCO,turn on your entire load and let them see what your actual connected load is.what type of equipment are you connecting?
Just a thought
Geo
 
  #4  
Old 12-01-14, 06:47 AM
Member
Thread Starter
Join Date: Dec 2014
Location: United States
Posts: 12
Hey geo, thanks for the reply. They have sent 6 engineers out here now. And they all dont know crap it seems. they all say "Well you shouldn't have that much load at a residence" or "It should be ok". They even used the special tools and took the measurements at my meter. They are a union publicly owned company, so in other words, getting them to do anything is impossible and slow, but they love to charge you money. I even spoke with the head engineer (The boss of the bosses) and he was really no help. So, I am on my own here.

I have used 3 different calculators liek this Transformer Calculator and according to them single phase 120v is half that of 240v. Am I looking at this wrong though?
 
  #5  
Old 12-01-14, 06:53 AM
Member
Thread Starter
Join Date: Dec 2014
Location: United States
Posts: 12
I know that 240v increases your capacity on my side, but I am more referring to the load it places on a transformer. I originally had 240v because it required less wiring for the same load, and the power supplies ran a little more efficiently, but I am pretty sure a transformer can handle half the load of 240 as 120. Something to do with there being no neutral on 240v possibly?


Here are a couple of the calculators I have been using

http://www.t-r.com/transformercalculator.aspx

http://www.csgnetwork.com/xformercalc.html

http://www.rapidtables.com/calc/elec...Calculator.htm
 
  #6  
Old 12-01-14, 08:14 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,385
So I have a 200 amp constant load from a data center type of environment.
When the 25 KVA transformers blew I was running all my equipment on 240v but I have now converted it all to 120v after reading that 120v will put half the load onto the transformer.
A 25 KVA single phase transformer is good for 104 amps at 240 volts or 208 amps at 120 volts. The transformer is definitely overloaded. Since you have converted your loads to 120 volts, you probably have a serious imbalance problem on the two legs. I'd transfer the loads back to 240 volts and request a 75 KVA transformer. You are evidently trying to run all your load from a residential single phase service and the power company may not have sufficient power available in your neighborhood for this kind of load.

I did a calculation that says the 50 KVA transformer should be good for just over 400 amps of constant load at 120v and 200 amps of 240v, does this sound right to you?
A 50 KVA single phase transformer is good for 208 amps at 240 volts or 416 amps at 120 volts.

The load chart was filled out when I had the 400 amp service installed so they where aware of my requirements.
Can you post a copy of the load sheet?


This isn't rocket science. Even with a 50 KVA transformer you have too much load.
 
  #7  
Old 12-01-14, 08:35 AM
Member
Thread Starter
Join Date: Dec 2014
Location: United States
Posts: 12
Thanks for the reply. I have 200 amps at 120v on a 50 KVA. They upgraded the 25 kva to a 50 KVA. Is that still overloaded? The load is distributed on 3 200 amp boxes. I am confused, the 50 KVA is good for 400 amps of 120v but 200 amps of 120v is overloading it? Is the because its constant load?

Your saying I should wire it back to 200 amps of 240v and the 50kva is only good for 200amps of 240v but thats better? This really makes 0 since to me at all. I thought it would be better to ahve a 50% load of 120v then a 100% load of 240. Anyone explain this?

The sheet I don't have, that was done by the electricians. I did not wire any of this myself.
 
  #8  
Old 12-01-14, 11:41 AM
Member
Join Date: Nov 2012
Location: USA
Posts: 3,314
Maybe this will help,you may need to get your electrical contractor involved with the POCO,also computer loads can be a problem with their switching power supplies.
1PH Amps
Geo
 
  #9  
Old 12-01-14, 12:31 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,399
They are a union publicly owned company,
What the heck does THAT mean? Where do you live (city) and what is your serving utility?

I think you are confused about the way that transformers are connected when you explain about converting the loads to 120 volts. Almost all residential transformers are connected with a center-tapped 240 volt secondary winding and this means that while the kVA rating of the transformer may give amperage ratings at both 240 and 120 volts that 120 volt load MUST be "balanced" across the center-tapped winding. You are definitely better off running as much as possible at 240 volts to eliminate the unbalanced load.

Also, data center alludes to switching power supplies (as stated by Geochurchi) and THIS type of load often has higher than expected neutral currents. Data centers routinely use "K-rated" transformers that are specifically made for these loads although I am unaware of utility distribution transformers having K ratings.

A single 50 kVA transformer would supply a 200 ampere residential service, NOT a 400 ampere service. Due to load factoring and the tremendous short-term overload capability of oil-insulated utility distribution transformers a 50 kVA would often serve multiple homes, each with a 200 ampere service rating. For example, my home has a 50 kVA pad mount that also serves three other neighbors but because our homes are typical that transformer probably never is loaded anywhere near 50 kVA for more than a few minutes at a time.

Utilities are loathe to install distribution transformers any larger than necessary because of two primary reasons, the first is the capital cost and the second is the operating cost. A lightly loaded transformer uses more power in that condition just for magnetizing the windings. Since the transformer is before the kilowatthour metering this power is a net loss to the utility. Keeping the transformers minimally sized can drastically reduce the amount of power that is lost system wide.
 
  #10  
Old 12-01-14, 01:24 PM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,515
Your computers should be connected at 240V where possible. The 50kVA transformer is undoubtedly overloaded in either case. You ideally don't want to exceed 80% on the transformer and you're basically at 100%. For powering a data center type load, the transformer really ought to be K-rated to handle the harmonic load introduced on the neutral.

The power company has completely different obligations, designs, specs, etc for a residential service than for a commercial service, which is the problem you're running in to. A residential 400A is designed for 320A continuous / 400A peak. Don't get hung up on the public owned, union stuff -- you're exceeding specs on a residential 400A service and that's what they've told you. Every other power company I know of will tell you the same thing.

You either need to shed some of your load, or get a commercial electrical contractor out to design a proper service entrance for this data center. It depends on the local regulations, but you may not be able to get the size service you want at a residential property due to the grid design. You may need to move to a commercial location to get big enough lines to support it. This isn't because the power company hates you, it's because they run certain size lines to residential developments and pulling too much load will adversely affect your neighbors.
 
  #11  
Old 12-01-14, 05:13 PM
Member
Thread Starter
Join Date: Dec 2014
Location: United States
Posts: 12
Thanks, i already have tried. I ahve talked to literally every engineer they have now and the main engineer himself.
 
  #12  
Old 12-01-14, 05:21 PM
Member
Thread Starter
Join Date: Dec 2014
Location: United States
Posts: 12
on the 400 amp service I am using 150 amps on two 200 amps panels that each have their own drop to the transformer, thats 75 amps of 200 per panel (And less then 50% of the meter rating). I am using another 50 amps and a 3rd 200 amp panel with its own drop to the transformer. No panel is over 40%. My 50 KVA transformer is rated at 400 amps of 120v and I am using 200, so thats 50% of its rated load. Am I looking at this wrong?

Everyone keeps saying call the power company, but i have! They are no help. I had engineers design this, the power company and electricians installed it. It as then inspected and the power company turned it on. This was all done 12 months ago and they installed a brand new box just for the 400 amps service.

is a 50% load on a transformer ok?
 
  #13  
Old 12-01-14, 05:28 PM
Member
Thread Starter
Join Date: Dec 2014
Location: United States
Posts: 12
50% load of 200 amps of 120v on 50kva transformer ok?

So my math says a 50 kva transformer is good for just over 400 amps. Is a single phase 200 amp 120v constant load ok?
 
  #14  
Old 12-01-14, 05:42 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,399
No, the new thread should be deleted.

Why won't you answer my questions as to where you are and what is your serving utility?

You are confusing the issue when you ask about 120 volt vs. 240 volt loads on the transformer since almost all distribution transformers will have a center-tapped transformer as I already pointed out to you.

Why not draw a rough sketch of your installation and post it? I think I understand what you have but I would prefer to work from YOUR sketch.

I also do not believe that you have spoken to the proper person at the utility, this is NOT open-heart surgery but it IS more than a standard residential installation. Sometimes it takes a little perseverance to get the proper person who will understand the problem.
 
  #15  
Old 12-01-14, 05:55 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,052
I have merged in your new thread and archived unneeded replies.
 
  #16  
Old 12-01-14, 07:09 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,385
on the 400 amp service I am using 150 amps on two 200 amps panels that each have their own drop to the transformer, thats 75 amps of 200 per panel (And less then 50% of the meter rating). I am using another 50 amps and a 3rd 200 amp panel with its own drop to the transformer. No panel is over 40%. My 50 KVA transformer is rated at 400 amps of 120v and I am using 200, so thats 50% of its rated load. Am I looking at this wrong?
It would be better if this discussion was in KVA rather than amps. I sense you are not understanding the loading and balancing issues here as well as not answering questions needed to attempt to give you answers. You also told us in post #1 that you have 2 services, but now you have 3 drops from the transformer. My best recommendation is to hire a commercial design/build contractor to review what you have and design it properly keeping the loads balanced. Your contractor will also have a hotline to the engineering department at the utility.
 
  #17  
Old 12-01-14, 08:08 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,284
I think the problem here is that you are running a business out of your home that is using more than the "normal" amount of power of a standard house.

The other problem is not the panel loads, they are all within the ratings of the equipment, it is the total load you are putting on the transformer that is supplying your home. Also the calculations that you are doing to figure transformer sizes is wrong.

Normally when we install a transformer that takes 480v (3 phase) and drops it to 120/208Y (3 phase) we use a 75 KVA transformer. Using your calculator you posted Transformer Values Calculator 3 phase @ 208v @ 200 amps gives me 72 KVA. The closest match to that is a 75 KVA transformer.

So my math says a 50 kva transformer is good for just over 400 amps
Your math is wrong. With your load single phase of 200 amps at 240 volts (which is what you have coming into you home) gives you 48 KVA. This means that a 50 KVA should work. However you are on the upper end of that transformer. The transformer does not care if it is 120 volt load, or a 240 volts load, It all goes back to the transformer.

Here's the rub. The power company can, and will charge you if you burn up that transformer and they have to install another one. It is not because they are mean. It is because you have a non-normal load for a house. They could even say, "No, we are not going to increase the size of your service" You need to either stop adding more load to your electrical service, or move your business to a commercial building with the electrical requirement you need.
 
  #18  
Old 12-01-14, 09:55 PM
Member
Thread Starter
Join Date: Dec 2014
Location: United States
Posts: 12
There are 2x 120v lines running into each panel and together would make 240v, but I thought if you where running 120v part of that load gos into the nutral (3rd wire running into the box from the transformer) and that's why it's less of a load. Where 240v dose not have a nutral and all the load is on the two wires.
 
  #19  
Old 12-02-14, 01:02 AM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,399
The transformer secondary winding is 240 volts. There is a center tap on that winding that allows for 120 volts from either end of the winding to the center tap. In order to get the rated current from the transformer the 120 volt loads MUST be balanced between the two halves of the winding. THAT is why 240 volt loads are preferred because they are inherently balanced.

Again I ask, why not post a sketch of the installation, from the utility's transformer to the metering and the various panels. There may be a relatively easy fix but when you treat us like mushrooms (keep us in the dark and feed us manure) we can't help.

And also post the name of the serving utility as well as your location (nearest city) and if you are way out in the sticks post that also.
 
  #20  
Old 12-02-14, 07:24 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,515
Everyone keeps saying call the power company, but i have! They are no help.
No, we're saying call a licensed electrical contractor who has some experience with commercial services, preferably involving computer loads. This is outside the scope of a typical residential job.

It's very unlikely you'll get anything more out of the power company without converting to a commercial service, if that's even allowed. When doing so you may need stamped plans and will almost certainly need a licensed contractor to get the permits and the design specs to the power company's distribution engineers.

We can give you some pointers on how to proceed and how to hire a contractor if you post some details about the loads, panels, service drops, layouts, sketches, etc. But because it's basically a commercial job the actual paperwork will need to be done by someone licensed in your state.

Another possibility is that if you are out in the sticks you might have an agricultural zoning which can help with getting a large service installed in the middle of nowhere. A contractor who knows the power company could help you with some shortcuts like that.
 
  #21  
Old 12-02-14, 07:44 AM
Member
Thread Starter
Join Date: Dec 2014
Location: United States
Posts: 12
Thanks for the reply, but none of this is an option, I already spent all my savings getting this going (Was $7,000 just for the 400 amp service install!) Unless you guys want to make a huge cash donation to my cause, lol.

I really just need to know how much power is safe to push on this 50 KVM transformer.

An everyone, please stop giving me a hard time. I have been 100% transparent wit the power company, they knew what my requirements where and all the work was professionally engineered and installed by licensed electricians!!!!!!!!! I got screwed over on this deal and dont have the money to correct it because, as I said above, I spent it all. Even if I did have the money, I don't have the time, I work 15 hour days, 7 days a week.

So please guys, just throw me a bone here and just tell me some safe numbers. The power company claims I am ok, but I dont think half of them know much about transformers, seems they just keep upgrading them as they blow.
 

Last edited by tech1801; 12-02-14 at 08:58 AM.
  #22  
Old 12-02-14, 07:58 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,515
I know this answer won't help much, but the safe amount to use on a 50 KVA transformer is less than 50 KVA. Which depending on the specific characteristics of the load is somewhere between 125A and 210A when the load is connected at 240V. The reason for the variability is that we don't know the power factor of the load, I will take a wild guess that it is about 0.75 based on a description of mostly switching DC power supplies. That would place a safe upper limit on the transformer of about 160A at 240V for continuous operation. If you also have air conditioning units we'll need to back off that number a bit, and a lot during summer.

If your service was installed by a licensed electrical contractor, who knew the load profile, I'd say they didn't do the job correctly and you do have some justification to call them back out and at least try to get some money back. Somebody didn't do something right. My fear is that they didn't tell you what you wanted wasn't possible/practical and took the job anyway. Sometimes good customer service is telling the customer no.
 
  #23  
Old 12-02-14, 08:42 AM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 21,023
Tech...I have to say...you are talking with some very qualified, very experienced people here. Pretty sure Furd worked commercial power plants. ipbooks is one of our most knowlegable electrical guys (no offense to anyone else). CasualJoe is a Master (I think?) and has been doing this for almost 40 yrs. TI is also a Master (I think).

Anyway...they have given advice and asked questions which you really haven't answered completely. Drawings, specs, type of load, etc.....

None of our Pros are there and can walk around and look at what you have. It's like saying "I have something in my eye, how do I get it out."
 
  #24  
Old 12-02-14, 08:46 AM
Member
Thread Starter
Join Date: Dec 2014
Location: United States
Posts: 12
Thanks for the reply :-)

I think the electricians did a good job doing the wring, it was just the power company didnt not upgrade stuff on their end as they where supposed too.

What would you say is a safe load on 120v? When I changed to 120v from 240v I noticed a huge drop in the harmonics coming form the transformer, its almost silent now, before it was pretty audible. At 240V I was getting case readings as high as 113 deg, since converting to 120v, I have yet to see any above 75 deg (I am using a thermal gun and measuring the hottest spot found on the outside case).
 
  #25  
Old 12-02-14, 09:06 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,515
I find that very surprising! On the gear that was connected 240V and is now 120V, is it all multiples of identical equipment? Are the power supplies directly on the line or do you have UPS units in between? What are the makes/models? There is no good reason 120V would perform better than 240V unless it is some weird quirk of that particular machine.

If the transformer is at 75F, then it is well inside the safe zone. Is this a ground mounted transformer or hanging up on the pole? Generally speaking the transformer is ok if it is no hotter than the ambient air temp (in C) plus 55C. Some transformers can withstand a lot more heat than that depending on type. Can you post a picture of it?

Does your electrical contractor know about the burned up transformers? If you work through them they may be able to make some calls to the power company if the original job was supposed to include poco upgrades that never happened. It's really their responsibility to follow through on completing the job, including interfacing with the power company, paying permits, filing paperwork, etc.
 
  #26  
Old 12-02-14, 09:14 AM
Member
Join Date: Nov 2012
Location: USA
Posts: 3,314
I believe we have said several times that the safe load on that transformer (50 KVA not KVM)is roughly 200 Amps,what part of that do you not understand?usually one would not like to exceed 80% of the rating or about 160 amps to make matters worse.
Geo
 
  #27  
Old 12-02-14, 10:34 AM
Member
Thread Starter
Join Date: Dec 2014
Location: United States
Posts: 12
I appreciate that advice, however I am not really interested in 240v, most of my load is 120v. Every sizing calculation I have seen says 400 amps at 120v . I read 10 pages of a collage text book on electrical engineering on proper sizing of transformers, and the math I found in those books leads back to the same thing, 400 amps. However, they all agree with you on 240v, 200 amps.

I have looked at about 20 sizing charts today, and they all say the same thing. 400 amps at 120v

What am I missing?

Name:  transformer-full-load-single-phase.jpg
Views: 10206
Size:  32.4 KB
 
  #28  
Old 12-02-14, 10:47 AM
Member
Thread Starter
Join Date: Dec 2014
Location: United States
Posts: 12
and I know its KVA, that was a typo (You cant edit the subject after making a post, nice try at a stab there though). I am actually a network engineer by trade and know a little about this stuff.
 
  #29  
Old 12-02-14, 11:21 AM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 21,023
Actually...you can edit...but there's something like a 45 min window.

I'm no electrical engineer or electrician...but yes...normally if you halve the voltage you double the current. Electronics in the Navy always specified fuses for both 240 and 120. 240 was half the 120 requirement.

Supplies and transformers like you describe may be quite different.

Once again...a simple diagram of how your system is set up might be a great help. Do you have NO 240V loads in the home? Dryer, oven, water heater, etc?
 
  #30  
Old 12-02-14, 11:48 AM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,399
I am going to state this one last time and then leave.

Your transformer has a center-tapped 240 volt secondary. To use it at maximum capacity at 120 volts you MUST balance the load between the center tap and each end connection. ONLY with a balanced connection will you be able to pull a total of 400 amperes from a 50 kVA transformer. Even then, depending on the type of load (nonlinear if using switching type power supplies) you may be limited to significantly less than 400 amperes.

Transformers are rated in kVA rather than amperes for a reason. ALL calculations of load need to be done using kVA ratings and NOT amperes.

Dry transformers have a much lower overload capacity than do oil-insulated transformers. As has been stated, a continuous load on a transformer should not exceed 80% of the rating. For a 50 kVA that would mean no more than a 40 kVA continuous load or about 160 amperes at 240 volts, 320 amperes BALANCED at 120 volts. IF your load is mostly switching type power supplies you MIGHT have to derate as much as 50% from these figures, again, depending upon the specifics of the transformer in question.

There are several possible ways to make this all work but since this is a top-secret installation I seriously doubt that you will get the required information from any Internet forum.
 
  #31  
Old 12-02-14, 01:23 PM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,515
400A @ 120V and 200A @ 240V are exactly the same thing assuming perfect balance between the legs. Since this isn't a theoretical physics problem, we know that situation is impossible and assume some imbalance exists. How much? We don't know.

This still skirts the major issue I alluded to above that you've only been working in real power (watts). Transformers are rated in (volt-amps), a unit of apparent power which takes into account the complex (p+qj) nature of other-than-resistive loads. If you were powering nothing but Edison bulbs, this would be an easy calculation; however since a significant portion of the load is DC power supplies, and another significant portion is presumably induction motors, your power factor is significantly off unity (but we don't know how much or in which direction) making the simple volts and amps calculation pretty meaningless. Add to this another huge complication that a pile of DC power supplies can introduce an non-linear harmonic in the neutral adding significant current on what is often an undersized conductor. It is not a straightforward calculation, nor is there a cheap fix.

Here is an article from a transformer manufacturer that gives an overview of the problem, and how special types of transformers can be deployed to correct it: http://www.hammondpowersolutions.com...nic_KRated.pdf

At this point I can say is a complete rough guess of somewhere around 150A @ 240V maximum continuous load on the transformer. Without good design documents there is nothing more that can be said. Watch the temp on the transformer and keep it less than 55C over ambient.
 

Last edited by ibpooks; 12-02-14 at 01:55 PM. Reason: Added article link
  #32  
Old 12-02-14, 06:45 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,284
One thing that has also not been mentioned: If this is the power companies transformer, they can pretty much do what they want as far as sizing transformers (among other things). Power companies are not bound by the NEC and regularly push their transformers 100%, or more, of their rating. If they say your are OK, then I tend to believe them. However, I do not think you have any room to grow without possibility damaging the 50 KVA transformer.

That sound you hear is not harmonics, it is 60 cycle hum. Harmonics are an entirely different thing. (Google "electrical harmonics")

I will also reiterate: 120 volt, 240 volt, it doesn't matter what the voltage is, (you have a 120/240 volt system) it is the amps. It all goes back to the transformer. I suspect the reduced temp of the transformer is due to a more balanced load.

(Was $7,000 just for the 400 amp service install!)
That's nothing. Company we do work for had a 400 amp 3 phase 120/208v service added to their building with an upgrade of their transformer. It was $43,000.

Just for the record, not a Master, just been around the block a few times.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes