Resi Main AIC

[chris kennedy]

I'm bidding a couple hundred cake service changes. The same can is still available and company owner wants it bid to use the old main in the new can.

Existing main is 150A 10,000AIC. Is 10,000 typical for resi? Thought is was 22k.

1747

[mdshunk]

10K is all we've ever needed here most of the time, but I see a lot of the equipment now is 22K anyhow.

[480sparky]

Older stuff is typically 10K. Newer is rated 22K. You may not me able to use the breakers. Contact your utility to see what the fault current is on their transformers.

[chris kennedy]

Contact your utility to see what the fault current is on their transformers.
Thats what I figured but thought one of you people might say:

'Your an idiot Chris, typical resi trannys can't deliver over 10k.'
I only went to look at this because it was on my way home.

[480sparky]

.....'Your an idiot Chris, typical resi trannys can't deliver over 10k.' ....

Yea, Chris, but we know you don't look at the 'typical' jobs, either. ;)

[frizbeedog]

Existing main is 150A 10,000AIC. Is 10,000 typical for resi? Thought is was 22k.


Local Power Company here has recently changed their requirements for residential AIC to require 22k for up to 400amps.

[LarryFine]

The same can is still available and company owner wants it bid to use the old main in the new can.
Gee, what's wrong with the old can? It looks like it's equipped to drain.

[480sparky]

Gee, what's wrong with the old can? It looks like it's equipped to drain.

I think the word is arranged.

[LarryFine]

I think the word is arranged.Yeah, arranged, that's the ticket.

[charlie]

Local Power Company here has recently changed their requirements for residential AIC to require 22k for up to 400amps.
HMMM. The serving electric utility usually stops at the service point. Most electric utilities, will just give you the expected worst case available fault current and leave it up to you to determine what is needed for the AIC rating. With smaller transformers and up to 50 kVA, you will not have enough available fault current to need more than 10 kAIC rating unless the service is a large underground fed one and the transformer is on the nose of the service equipment. :smile:

[frizbeedog]

HMMM. The serving electric utility usually stops at the service point. Most electric utilities, will just give you the expected worst case available fault current and leave it up to you to determine what is needed for the AIC rating. With smaller transformers and up to 50 kVA, you will not have enough available fault current to need more than 10 kAIC rating unless the service is a large underground fed one and the transformer is on the nose of the service equipment. :smile:


From thier "Electric Service Requirements" Manual

1.5.2 Single Family Residential (201 to 400 Amps)
For single family residences with services in the range of 200 to 400 amps,
the Customer is responsible for furnishing equipment that will withstand a
maximum 22,000 amps fault current. For services larger than 400 amps,
PGE will provide the maximum available fault current to the Customer upon
request.


Originally I posted that it was for up to 400 amps, but it is for 201 to 400 amps.
I provided a link for you to entertain your confusion. I haven't asked for an explaination, it was new this year. They must have thier reasons.

Electric Service Requirements. See chapter 1 (http://www.portlandgeneral.com/business/builders_and_dev/install_requirements.asp?bhcp=1)

[charlie]

They must have their reasons.
I am guessing that their reason is to make sure that they are not liable for someone selecting the wrong AIC equipment and to keep from putting together any charts that would show what their maximum available is for their various sizes of transformers. In other words, I believe that they are lazy and are afraid of a lawsuit. :)

[chris kennedy]

With smaller transformers and up to 50 kVA, you will not have enough available fault current to need more than 10 kAIC rating unless the service is a large underground fed one and the transformer is on the nose of the service equipment. :smile:
I will call POCO Monday as I looked at a couple of the 20 year old pad mounts and the name plates are gone. These trannys feed 4 units each so from what you describe sounds like 10k is OK.

Of topic but an update. Still no POCO lock on the vault (http://forums.mikeholt.com/showthread.php?t=99333&highlight=bats)as of yesterday. Going on a month now. Thats how FPL rolls.

[bikeindy]

Chris, I hope you are charging extra to work on a pink house, I would.

[CopperTone]

I hate reusing old stuff - why not just install all new mains? If they fail - they'll blame the EC - if you break it during disassembly, you would be blamed and on the hook to replace it - if it doesn't work after you reinstall it - even though you didn't do anything wrong you'll get blamed - you'll get blamed for anything for the next year - don't use old crap. Plus, you drive down the price on the job, and when a company who believes in doing things right bids the job - they lose it to companies that are piecing the job together.
I know I'm not in this business to help out the guy who needs a lot of work done cheaply. I do lose bids to guys who cut corners and the people who are comparing the bids aren't looking at the same job - apples and oranges - but all they see is the price and think they are getting the same job for a lot less money. Why do most of the job right? Heck, why not just buy some sheet metal and repair the rusted out cabinet - that would save the owner a ton of money - and you'll be out of there in no time.

BTW - I have a saying - If money is a problem, come back when it's not!

[mdshunk]

I hate reusing old stuff - why not just install all new mains?
The owner specifically wants to reuse the old mains. That's certainly his right. I take certain offense to the suggestion that reusing any part of the old service is not "doing the job right". I'm going to go out on a limb here and guess that you are not a business owner.

[CopperTone]

I'm not looking to get into a pissing match here. I do own my company - and for long enough to see down the road at potential problems, problems I'd rather not open my company up to. Sure, it's the owners right to reuse old stuff, I see it as my right to show the owner how to do the job right the first time. I can see the point that reusing old stuff isn't necessarily the "wrong way" but it certainly isn't the best way. You can take all the offense you want or look at it as possibly advice. best of luck either way.

Sometimes you have to learn the hard way to learn something at all.

[mdshunk]

Sometimes you have to learn the hard way to learn something at all.
...and sometimes you need to quit thinking like an ar-teist and think more like a businessman.

[CopperTone]

I am just glad that you don't work for me. You'd cost me too much money eventually. Hows that for business thinking?

[mdshunk]

I am just glad that you don't work for me. You'd cost me too much money eventually. Hows that for business thinking?
Why? Would you go back and replace a bunch of main breakers for free? I think not. Truth be told, I give "good", "better" and "best" options on small estimates like this, so they'd have their choice.

I am constantly puzzled by guys that won't do a job at all if they can't do it their way. A small slice of the pie is better than no pie at all. The profit is still the same. Matter of fact, the profit potential is probably greater on just replacing the cans alone in this case.

[CopperTone]

I don't think you are seeing my point. What makes you think the mains are still good for another 20 years if the rest of the service needs to be replaced. You see the rust rot - right? No water got in there? I believe that the original post said there were "several hundred" services to change. It will take time to do that job - and while it is going on and you find that, some don't work, they cracked when you took them out, lugs are stripped, they overheat and burn up before the job is complete, anything really, you think the owner of the building won't blame you and say - "well, they worked fine before you touched it."
The one paying the bill could hold up payment, and generally make your life miserable while it is sorted out in court for the next 10 months. Even with a contract that is specific.
Don't be deceived here, this is only about money - my money or your money or the other guys that does the job - his money. - And the owners money. I only wanted to offer my opinion that old stuff is exacly that -
Where I live everyone goes by this " you touch it, you own it".

Argue all you want in court - I would have gotten paid by then and been off to the next job making more money. Or undercut and moved on to the next job or bid.

Artists don't make money until they are dead.

[mdshunk]

I don't think you are seeing my point. What makes you think the mains are still good for another 20 years if the rest of the service needs to be replaced.
I don't think they will last another 20 years, but that's not my decision to make. I offer my opinion, then I sell them whatever it is that I can talk them into. I certainly would never refuse to do the job based on an expressed desire to reuse the existing breakers. Any lugs that strip out or break off would be change orders, and I'm certain that potential fact would be highlighted in the proposal. "You touch it, you own it" is a myth. It doesn't go down that way in real life with appropriate contract language.

[CopperTone]

Ok funs over, I'm going to bed but I'll leave you with this - We can disagree and that is ok. I would concentrate on selling a completely new system to the owner. I would be sure they understood the value in that. I personally think it is the proper way to to do business as well. If this was 1 main - I might let it slide with specific language in a contract. But for several hundered? no way.
I might just pass on bidding this job and get a slice of the pie somewhere else. At least I know I'll get to eat it when I'm done.

[mdshunk]

I would concentrate on selling a completely new system to the owner.
I would too, but I just wouldn't limit myself to that option in the end.

[iwire]

I see it as my right to show the owner how to do the job right the first time.

But your view of 'the right way' is just an opinion from your perspective.

Perhaps the customer does not care about how long it will last, maybe they are selling all these properties and simply want to fix what is necessary?

I agree with Marc.

I am constantly puzzled by guys that won't do a job at all if they can't do it their way. A small slice of the pie is better than no pie at all.

[DanZ]

Chris,

If you have a contract for this, make sure you stipulate that old breakers will be used where applicable, but due to the nature of everything some may not be usable and the building owner shall be liable for cost incurred related to the use of new breakers.

Or some such nonsense.

Don't forget to mention that they won't last forever, and you're not liable if the existing equipment fails.

Either way, they will probably want you to pay to fix anything.

Just my $.02

-Dan