Inspector-"I want to see some load calcs"

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sfav8r

Senior Member
thanks for all the replies. Let me clarify a couple of things.

I don't mind the load calc on the EXISTING installation. My complaint is that the inspector wants the calcs done with 2 appliance circuits per unit, 1 laundry circuit per unit, etc. even though these are 1 bedroom apartments that don't have those items. I think the calc. should be done on the ACTUAL existing load and my suggestion was to throw a monitor on the main and record the REAL demand which I think is reasonable. The inspector's opinion is that these units all get upgraded over time and therefore we need to install the service accordingly (let me emphasize again that I don't call this a new service). While I agree it would be nice to do, I think that falls under the category of opinion and is not enforceable. Keep in mind there really isn't an argument with the inspectore here, he told me what he wants and I'm deciding how I'm goin to proceed.

It seems logical to me that I am replacing 40 year old FP sub panels and installing new panels and breakers properly sized for the loads. Whatever load is on the main is not changing and has served perfectly fine for the last 40 years. The inspector suggested that if they can't do the entire job at once, that they wait until next year to do the entire job. To me this is just not a better solution from a safety point of view.

If this was a single family with a meter/main outside and an FP panel in the garage, would upgrading the FP panel without changing the service be a problem? The new service would be nice, but the safety is definately enhanced by swaping the panel out and IMHO there is no violation either way.

Finally, a previous poster commented that "the inspector has the right to know if a new installaion is overloaded." I agree completely. The new panels will not be overloaded and we are not touching the service.

Thanks again for all the perspectives. It's always good to see how other people perceive the same situation.
 
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George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
Wow, this is a tough row to hoe. You're not changing the loads, but there's a darn good chance that if they get their new panels then they won't follow through and replace the service later.

OTOH, they could probably cut a deal with the AHJ that the new subpanels will be safer, and they will get their property condemned at the end of next year if they do not upgrade the service.

If the AHJ won't work with you and the association, that would force a delay on the whole project until they can afford to pay for everything. Of course, then Sam the Sideworker may come along and change the panels when you're not looking, too. And you might bring that up with the AHJ as well.

Better an inspected installation that's missing a service for now, than no action at all. No action will either result in a fire, or uninspected work done on the side due to the inflexibility of the city and the disinfranchised owner, IMO.

I'd say you do a load calc, and take it to the city regardless of what the math adds up to. It's a necessary bit of information for all to make an informed decision.
 

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
My complaint is that the inspector wants the calcs done with 2 appliance circuits per unit, 1 laundry circuit per unit, etc. even though these are 1 bedroom apartments that don't have those items.
Yeah, but they don't exactly add a whopping amount to the load calc, either.

I think the calc. should be done on the ACTUAL existing load and my suggestion was to throw a monitor on the main and record the REAL demand which I think is reasonable.
Pencil and paper is quicker and cheaper. I guess you probably already own the recording equipment?
 

sfav8r

Senior Member
The point is, will the newly installed equipment be able to handle the load impressed on it?

If you were asked to replace a #12 wire that you knew had 50amps on it, would you just pull the old 12 out and put new 12 back in just because you're not 'updating' the circuit with new over current devices, new raceways, etc?
You are making a good argument to support my point. As you stated "the NEWLY installed equipment should handle the loads impressed on it" I am installing new sub panels and they are each rated at 125a and have OCPDs properly sized for the loads. So where is the problem?

As far as the #12 example goes, I don't see any connection (no pun intended). I am installing proper OCPD so how is the relevant? This example would only make sense if I said it was a 175a service disco with #8 feeders or something.
 

sfav8r

Senior Member
Yeah, but they don't exactly add a whopping amount to the load calc, either.


Pencil and paper is quicker and cheaper. I guess you probably already own the recording equipment?
Yes, we have a monitor and it takes all of 5 minutes to install. the thing I like about the monitor is it is real world. I realize there are seasonal variations, but a 1-2 week printout gives a you a pretty good idea of what's going on. The other advantage is I don't need to get access to each unit to itemize the appliances etc.
 

petersonra

Senior Member
You could probably do the load calcs in less time than you spent posting to and reading this thread. Do the calcs and see what they say.

Maybe the answer is to replace the service first and do the subpanels later.
 

Cavie

Senior Member
Location
SW Florida
If the existing units were legal at the time of instalation, and the loads fit the service size than the inspector is intitled to a load calc based on the existing loads only. He cannot demand todays loads standards for number of circuits and laundry loads that were not in existance at time of new instlation.
 
There is nothing in the NEC about what is and what is not required for inspection. Those issues are handled by each area. They can certainly request to see load calculations. The fact that in your area you have not had this request has nothing at all to do with what another area may request.



Very true, that can and does happen. I assume that when they see an engineering stamp on the drawings they take that as a sign the job has been designed correctly.

But many times there are no 'engineered' drawings at all, just a permit application with a job description. In that case it would seem prudent of an inspector to ask what the calculated load is.
I don't disagree. If you read my response I only suggested that the Inspector should provide the written and published rules and laws regulating his work and authority that would prove that his request is within his authority. (For all I know, he may have rules that dictate that HE should be doing the load calculations to verify that the system is appropriately sized. In that case he can politely request the data to save him some work.) The rules should be available to all Contractors and when the original permit is given the form should have a warning to review the rules before accepting the permit. That would allow everyone to play nicey-nicey and no such posts would be necessary.:smile:

I am very sensitive against abuse of authority. I grew up under such regime.
 

SEO

Senior Member
Location
Michigan
The rules should be available to all Contractors and when the original permit is given the form should have a warning to review the rules before accepting the permit. That would allow everyone to play nicey-nicey and no such posts would be necessary.:smile:

.
I agree. The permits that are issued out of our offices have said warnings to review specific rules stamped on the permit or application. I have witnessed contractors say that they have never heard of such a thing and it was stated on the permit application that they signed. Not to make excuses for electrical inspectors but like everything else read the complete application including stamped and small print.
 

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
Yes, we have a monitor and it takes all of 5 minutes to install. the thing I like about the monitor is it is real world. I realize there are seasonal variations, but a 1-2 week printout gives a you a pretty good idea of what's going on. The other advantage is I don't need to get access to each unit to itemize the appliances etc.
I don?t agree. 2 weeks of monitoring would not be of much use. Your monitoring equipment does not know if some of the units are vacant or if tenants are vacation. What happens during the winter when the tenants use portable space heaters? Load calcs take this into account but measuring demand over 2 weeks doesn?t.

I could do the load calcs for this building on a piece of scratch paper in less than 5 minutes. It would probably take me 30 minutes to put it in an Excel spread sheet and make it look nice.
 

radiopet

Senior Member
Location
Spotsylvania, VA
But many times there are no 'engineered' drawings at all, just a permit application with a job description. In that case it would seem prudent of an inspector to ask what the calculated load is.
Amazing enough I will assure you that having that "engineered" drawing and "stamp" on it means nothing when it comes to Code Compliance. I have first hand account of that on a daily basis doing electrical plan reviews and seeing many things done wrong from licensed P.E's. Not to diss on them, I am just saying seals alone do not make for a perfect electrical design.
 

ivsenroute

Senior Member
Location
Florida
Amazing enough I will assure you that having that "engineered" drawing and "stamp" on it means nothing when it comes to Code Compliance. I have first hand account of that on a daily basis doing electrical plan reviews and seeing many things done wrong from licensed P.E's. Not to diss on them, I am just saying seals alone do not make for a perfect electrical design.
Correct. I just reviewed a set of drawing for a residence being converted to a doctor's office and my plan review status letter rejected the stamped drawings and listed 27 defects in the prints. This was for all disciplines, not just electrical.

As far as the original post it is my opinion that we don't know if the existing service is actually adequate for the current load since no one knows what has been added or what was approved initially.

Changing panels in many cases allows more room for more circuits to be added and simply asking for load calculations is certainly within the right of the inspector and or building code official who is charged with safeguarding the safety and health of the public by enforcing minimum standards.

Don't think the NEC is the only book that you go by in this case. There may be the IBC, local or state ordinances too. All which support the inspectors request.

You can get others here to tell you what you want to hear, which won't help you with the inspector or you can do what was requested so that you can get a permit, perform the work and earn money to support your family.
 
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Jim W in Tampa

Senior Member
Location
Tampa Florida
Cant say that 175 amps divided by 6 sounds good. Will say what your doing is making things bit safer. Part i hate is a FP main that might as well be 1,000 as it might never trip. Why can't they get a loan and get total job done now ?
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
I have a couple of buildings in town that I have never been in even as a private party. So who knows what's been going on for the last 20 years. Now's a great time for the inspector to find out if everything is up to snuff. Many a load calc has reveled that the load is more than it was thought to be.
 

Mr. Bill

Senior Member
Location
Michigan
220.87 (2005)
Thank you for someone bringing this up. Ask the tenants to see their Utility bills for a peak demand printed somewhere on the bill. Or stick a meter in the main for 30 days. But if one season is known to be a higher demand you'll need to measure during that season. It can be time intensive but sometimes useful.

The main downside to this is you need to add 25% onto the measured peak. So if you measured a peak of 150A which wasn't ever a problem on the 175A service you may be forced to increase this because with the 25% extra the load is determined to be 187A.

If the NEC gives and option for measurement or calculation then it's the designer's choice on what to provide.

I had a project with an annoying owner rep. We're replacing the service on the 80 year old high school. Just about doubling capacity and based it on existing utility bills and school's plans for foture loads in a few years. This owner rep kept saying I had to size the service based on the connected load in the school. There's no way I'm going thru the entire building counting lights and recepts and god knows what else. So what good would he have made by getting his way? The service would probably be 4 times larger and underused. He seemed to love spending everyone else's money. I still get my blood pressure up thinking about him. NEC gives me, the designer, choices on sizing. I'm using that choice.
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
I would accept the utility bill(s) if they can be produced. Did this at a car dealer, they had a 4000 amp service and at no time was their load over 1500 amps.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
Thank you for someone bringing this up. Ask the tenants to see their Utility bills for a peak demand printed somewhere on the bill. Or stick a meter in the main for 30 days. But if one season is known to be a higher demand you'll need to measure during that season. It can be time intensive but sometimes useful.

The main downside to this is you need to add 25% onto the measured peak. So if you measured a peak of 150A which wasn't ever a problem on the 175A service you may be forced to increase this because with the 25% extra the load is determined to be 187A.

If the NEC gives and option for measurement or calculation then it's the designer's choice on what to provide.

I had a project with an annoying owner rep. We're replacing the service on the 80 year old high school. Just about doubling capacity and based it on existing utility bills and school's plans for foture loads in a few years. This owner rep kept saying I had to size the service based on the connected load in the school. There's no way I'm going thru the entire building counting lights and recepts and god knows what else. So what good would he have made by getting his way? The service would probably be 4 times larger and underused. He seemed to love spending everyone else's money. I still get my blood pressure up thinking about him. NEC gives me, the designer, choices on sizing. I'm using that choice.
Would tell him to go do the calc and show the math.
 
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resistance

Senior Member
Location
WA
Seems like someone's trying to avoid doing the calculation for some odd reason. I say, "Just do the calculation!"
 
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