Failed Inspection... What Gives?

[panic_button]

I had a licensed contractor install ATS even though I will be manually switching over to the MEP-3. The ATS is service disconnect also per specs. The inspector comes out today to approve the work. He all but done, says everythig looks great then asks to see the generator. Electrictian states generator is not ready to be installed yet, and it on the driveway. The inspector looks at the generator and says he won't approve the rest of the permit. He states that based on NEC rules I need a minium of 35KW generator. I chime in stating that the 10kw is at .8PF and it would be 12KW based on the 1PF that commercial units are rated at. He still says no way... So I come up with another plan, I have 2 MEP-3's currently, and if I run each one at 120v only I have 104A each to each leg of the switch, a total of 208A for both, well over the 200A service I have (actually 180A, they put in 2 -90A mains). He still says no way. I asked him how I can have 200A service from the power company, 200A breakers, the generators will put out over 200A easily why this won't work. He says it's against NEC code. I pull up the Kohler & Onan sites to get specs fro thier 35K commercial units Onan's biggest is 20kw on the web listed at 167A, Kohlers 40kw is 154A, I show him the mine will be over the amps that both of them are rated, and that a 40KW has less amps that the 20kw. He tells me it has to be at least 35kw to pass inspection...

Anyone with experience chime in on this besides changing over to a MTS. I'm not against a MTS.

 

[Marcel]

It is better to ask forgiveness than to ask permission.

 

[panic_button]

Since it's not a commercial unit I told him the only spec is on the tag. He stated that was fine as that is what they go by for older units.

I am getting ready to load up the gen's and move them to the neighbors and have them pass the electrical part and cancel the generator permit

Anyone have a MEP-005 or 6 tag they want to get rid of?

 

[DieselBob]

He states that based on NEC rules I need a minium of 35KW generator.

I would like to know how they come by that. Not being a electrician I fail to see the logic in even stating a minimum rating for a generator.

 

[Carl_in_NH]

You can't run two seperate gensets in 120V mode powering each leg; Your 240V loads will see anywhere between 0V and 240V as the generators will not be locked in phase with each other.

I'm with the other comments; it's none of his business how big the genset is.

 

[panic_button]

I would like to know the how they come by that. Not being a electrician I fail to see the logic in even stating a minimum rating for a generator.

Here's the info he gave me:

2800sq ft house x 3w = 8400w
Range = 1990
Refrig (x2) 1500 =3000w
Water Heater = 9000w
Dishwasher = 1300w
AC/HP (5T) = 8500w
Dryer = 4500w
Washer =1200w


Comes up to a little under 35000 watts /1000 =35kw gen set per NEC & inspector.


I know and so does everyone else you would run everything at one time, but thew county thinks you will...

 

[panic_button]

You can't run two seperate gensets in 120V mode powering each leg; Your 240V loads will see anywhere between 0V and 240V as the generators will not be locked in phase with each other.

I'm with the other comments; it's none of his business how big the genset is.

I know that, but the concern is the "KW rating" on the generator, not what the set will actually do.

I'm going to call Delk's in the morning and see if they have a data plate for sale for a MEP-5 or 6.

 

[Carl_in_NH]

It's also interesting they think you're going to bathe the entire house in 3W/sq. foot of electric light at all times. Madness.

Is this only a rule for ATS installs? How about manual switching? I don't know _anyone_ that has a genset configuration that would allow maximum load with everything on at the same time - it would cost so much to run in fuel bills that you'd just end up sitting in the dark anyway.

 

[bmwsyc]

I hate to say it, but an inspector is right, even when he is wrong...from what I have seen, many are stubborn enough to hold their ground even if the decision is suspect. I also looked up Optional Standby Systems in the code book, and unfortunately, it's pretty specific about sizing the standby source to the load. Article 702.5.

 

[panic_button]

If I put in a manual switch they could careless of the rating of the generator as you can switch off breakers and I have to Manually switch it over.

The issue is the ATS says "Automatic" and per specs starts the generator. I tried to explain this wouldn't happen with the current generator, but he was sted fast that because it was an "Automatic Transfer Switch" they have to rate it per NEC

 

[DieselBob]

I hate to say it, but an inspector is right, even when he is wrong...from what I have seen, many are stubborn enough to hold their ground even if the decision is suspect.

Been there, done that, got the t-shirt. Was my own GC and electrician and plumber when we built our house. That is an experience I won't soon forget.

If I put in a manual switch they could careless of the rating of the generator as you can switch off breakers and I have to Manually switch it over.

The issue is the ATS says "Automatic" and per specs starts the generator. I tried to explain this wouldn't happen with the current generator, but he was sted fast that because it was an "Automatic Transfer Switch" they have to rate it per NEC

Hate to say it but they have you there. I learned real fast never, never, never, did I say never spec an item that you won't use exactly the way it is designed when you are dealing with code and inspectors.

 

[KsM715]

I hate to say it, but an inspector is right, even when he is wrong...from what I have seen, many are stubborn enough to hold their ground even if the decision is suspect. I also looked up Optional Standby Systems in the code book, and unfortunately, it's pretty specific about sizing the standby source to the load. Article 702.5.

No he is still wrong. 702.5 states that the transfer system shall be suitable for the intended load. and that the user of the standy by system shall be permitted to select the load connected to the system.

In other words the OP can tell the inspecter he only intends to run a fridge and the blower on his furnace if he wants too.

 

[DieselBob]

No he is still wrong. 702.5 states that the transfer system shall be suitable for the intended load. and that the user of the standy by system shall be permitted to select the load connected to the system.

In other words the OP can tell the inspecter he only intends to run a fridge and the blower on his furnace if he wants too.

Now that would make sense.

 

[glcaines]

I used a manual 400-amp 4-pole transfer switch I found on e-bay with my MEP-003A hooked to whole-house 400-amp service. You could always buy a manual transfer switch and sell the automatic switch. My installation passed both the county electric inspector and the EMC inspector as well. Make sure you don't alienate the inspector or you might never pass no matter what you do.

 

[panic_button]

No he is still wrong. 702.5 states that the transfer system shall be suitable for the intended load. and that the user of the standy by system shall be permitted to select the load connected to the system.

In other words the OP can tell the inspecter he only intends to run a fridge and the blower on his furnace if he wants too.

Am I screwed, per (B)(2)...

702.5(B) ​

This section is important to understand in that although the load applied to the system is always determined by conformance with NEC 220, this load does not determine the size of the optional standby system. The type of transfer equipment employed determines the size of the optional standby system.​

702.5(B)(1) ​

provides that when manual transfer equipment is used the “user” of the system is permitted to manually select the load connected to the system. This can be as simple as the user turning off selected circuit breakers. This rule permits the sizing of the system to be solely at the users discretion.​

---->>> 702.5(B)(2)​

​

provides that when automatic transfer equipment is used that (in the absence of automatic load shedding) the standby system shall be sized to the full load being transferred.​

 

[panic_button]

I used a manual 400-amp 4-pole transfer switch I found on e-bay with my MEP-003A hooked to whole-house 400-amp service. You could always buy a manual transfer switch and sell the automatic switch. My installation passed both the county electric inspector and the EMC inspector as well. Make sure you don't alienate the inspector or you might never pass no matter what you do.

I'm going with the manual, the issue is trying to find a service disconnect rated NEMA3 one per code here...

No issues with the inspector, he was very understanding and saw my point, he said if he could he'd pass it. This after drinking a gallonm of sweet tea waiting for the power company to show up in thier 2 hour window. At first he thought the MEP-3 was a 30+kw unit. He couldn't believe that it was only rated for 10KW.

 

[skidunits4you]

As per 702.5(B)(2) The inspector is correct with an ATS everything must be automatic. The Manual switch is your best bet and then you can pick the load

 

[KsM715]

Hmmmm what code are you using? I have the 2005 code book and it does not have those sub articles or what ever you call them All the 2005 has is a simple 702.5 I would say find out what code year they are under. Some cities are behind by a few years and have not adopted the latest codes. Now if that is in the latest code and thats what they are going by then you might be screwed unless you can convince them that your standby system automatically sheds the whole load by Not starting the genset. Your probably betteroff selling the automatic switch and going to a full manual switch.

 

[panic_button]

2008 code

 

[bmwsyc]

Yup, that was a change in the 2008 code.