Small generator

[iwire]

So what you are saying is that a homeowner is an approved means for doing a calculation.

Yes or more precisely the NEC allows the AHJ to decide that.

Why don't we just do away with Article 220 and just ask the homeowner what they want installed for a service

So what you are saying is that any user of a portable generator should be required to hire an electrician to perform load calculations each time it is put into service?

 

[augie47]

MIke,
My approach might be a little more common-sense.
If a homeowner wants a small generator to supply a part of his residential load and he goes as far as having an electrician wire it for him and an inspector inspect it, I'll think the intent of Art 702 is to allow "selection of load". Since the homeowner or someone must be on sitre to swith to generator power they can selectrively selct their load by use of breakers
connected to the system. Admittedly, there me be a bit of trial and error, but it's a method of selection.
I cerrtainly don't see where the inspector is in a position to decider which loads he selects. I know some folks using a gen. will turn a water heater on for 3 hours and select others loads to shed during that time, etc.
(B)(1) does not state how the load is to be selected.

With an automatic switching, that option is not there so (B)(2) does not give the the option to "select the load" at will.

 

[jwelectric]

Mike, on the flip side of that argument, I don't see anything saying the end user can't, and there is nothing in 702 saying that either, so I see this ending in a stalemate. :wink:


Roger

I respectfully beg to differ.

It clearly states in the main body of 702.5(B) that the load that is to be connected to an optional standby system is required to be calculated in some fashion or another. One method is by using Article 220 and the other method has to be an approved method.

Now unless you can find a code enforcement official out there somewhere that will say that a homeowner is an approved method of doing a calculation then the turning on and off of circuits is not allowed by the above mentioned section of the NEC.

What is being implied here is that most homeowners are as smart as we (electricians) are and know when they are about to do damage to the generator or equipment in the house.
Well most are not smart enough to know when this is going to happen. Most electricians aren?t this smart either or they wouldn?t be making such installations.

Now I wouldn?t have a problem with some sort of load shedding equipment that could do this for them.

 

[roger]

Actually, if we go back to the OP's question, 702 doesn't apply anyways.

Now, saying we do have a system that would be applicable to 702, trying to regulate what the end user does with it is as useless as 210.21(B)(2) is. :smile:

(For some reason I see this as being a portable unit)

Roger

 

[iwire]

Actually, if we go back to the OP's question, 702 doesn't apply anyways.

I do not understand? :-?

 

[jrannis]

I know this is kinda OT, but does anyone have a CH interlock kit they would like to get rid of for less than the $150 offered by the manufacturers?

What cat# number are you looking for?

 

[roger]

702.5(B)(1) also says,

Where manual transfer equipment is used, an optional standby system shall have adequate capacity and rating for the supply of all equipment intended to be operated at one time.

Anyonr doing the calculation can always say the end user only wants to use one 60 watt lamp at a time.

Worrying about and trying to regulate how someone will use an optional standby system is simply wasted ink in the NEC IMO.

Roger

 

[roger]

I do not understand? :-?

Once again, for some reason I see this as a portable unit, (I may be wrong) and 702 is for permanatly installed gensets.

Roger

 

[iwire]

I respectfully beg to differ.

It clearly states in the main body of 702.5(B) that the load that is to be connected to an optional standby system is required to be calculated in some fashion or another. One method is by using Article 220 and the other method has to be an approved method.

Here is what the CMP had to say on this

3. System capacity is now split into Manual Transfer and Automatic Transfer
applications. In addition text has been added to indicate how the load is to
be calculated. For instance if you are including the branch circuits in a home
that supply part of the general lighting load, how do you do that calculation.
The most logical approach is to use Article 220 and the new language makes
that clear. However, it is recognized that a number of jurisdictions are allow
recorded load measurements and similar information to be used to provide the
capacity. The new text would allow other methods that are acceptable to the
AHJ.

What is being implied here is that most homeowners are as smart as we (electricians) are and know when they are about to do damage to the generator or equipment in the house.

I am sorry, I thought we had to provide proper over current protection?

Following your line of reasoning homeowners need to perform load calculations when plugging loads into branch circuits to avoid damaging the equipment.

 

[iwire]

Once again, for some reason I see this as a portable unit, (I may be wrong) and 702 is for permanatly installed gensets.

Roger

From reading the scope of 702 it seems it could go either way. :smile:

If there is permanent transfer equipment with a portable prime mover I think 702 applies.

 

[roger]

From reading the scope of 702 it seems it could go either way. :smile:

If there is permanent transfer equipment with a portable prime mover I think 702 applies.

Oooops, I must agree.

Roger

 

[roger]

Now we have another problem, what happens if we buy another (different size) portable unit, do we have to go through another permit application with new calculations before we can use it with our permanently installed equipment? :wink:

Roger

 

[iwire]

Roger you know how it is, as soon as we try to put the homeowner and NEC together we have trouble.

210.21(B)(2) seems to be something that areas should start arresting homeowners for violating. :wink:

 

[jrannis]

What cat# number are you looking for?

The one I have is a K-1010.
They sent a replacement do the fact that the manufacturer changed the panel and not the cat#.

 

[roger]

210.21(B)(2) seems to be something that areas should start arresting homeowners for violating. :wink:

I agree, uhh, I'm going down to my basement wood working shop, I've got to check something, be back in a few minutes.

Roger

 

[jwelectric]

I respectfully beg to differ. It clearly states in the main body of 702.5(B) that the load that is to be connected to an optional standby system is required to be calculated in some fashion or another. One method is by using Article 220 and the other method has to be an approved method.

Here is what the CMP had to say on this

3. System capacity is now split into Manual Transfer and Automatic Transfer

applications. In addition text has been added to indicate how the load is to
be calculated. For instance if you are including the branch circuits in a home
that supply part of the general lighting load, how do you do that calculation.
The most logical approach is to use Article 220 and the new language makes
that clear. However, it is recognized that a number of jurisdictions are allow
recorded load measurements and similar information to be used to provide the
capacity. The new text would allow other methods that are acceptable to the
AHJ.

This is just what I have been saying from the start, ?a calculation MUST be made.?
It is also why I made this remark.

Now unless you can find a code enforcement official out there somewhere that will say that a homeowner is an approved method of doing a calculation then the turning on and off of circuits is not allowed by the above mentioned section of the NEC

I just don?t think that any code enforcement official will openly make the statement that turning off one circuit in order to turn on another would be an approved calculation.

What is being implied here is that most homeowners are as smart as we (electricians) are and know when they are about to do damage to the generator or equipment in the house.

I am sorry, I thought we had to provide proper over current protection?

I don?t think that overcurrent devices will provide any protection for over revving of a generator which will not only raise the voltage but the frequency.

Following your line of reasoning homeowners need to perform load calculations when plugging loads into branch circuits to avoid damaging the equipment.

It is not my reasoning it is the verbiage found in 702.5(B) of the 2008 NEC.
There is a good founded reason why Article 702 was addressed for the 2008 code cycle and most of it was due to complaints that the monies the homeowner was spending for a generator that wouldn?t work as they had been told it would.

We can understand things we know about such as the overloading of a generator but take some elderly person who has medical equipment plugged in on this little cracker box and has spent their life savings to have it installed and see if they understand that their oxygen has to go in order to make a cup of hot soup in the microwave.
This is one of the primary reasons why the loads MUST be calculated.

 

[roger]

Mike, IYO, when must the calculation take place?

Hypothetical situation, a new home is built and an interlock kit or a full fledged manual tswitch is installed but no generator is sitting in the garage, how does the AHJ or inspector have any control over what size generator will be bought or used?

Now, let's say it's an existing dwelling and the tswitch is permitted and installed but the Home Owner doesn't know if they will buy a generator or not but, they want to be prepared if they do buy one, does anyone really think they will run down to the building department with their calculations in hand?

Once again, IMO, this is a useless code requirement.

Roger

 

[electricmanscott]

Hey guys Ive got a friend who wants to have some of his house generator ready for hurricane season. He has all of his breakers in one panel. So what is out there to make this possible. What codes do I need to watch out for? Ive done whole house gensets but never a small one thanks

Please ignore all the hullabaloo between your original question and here.

What kind of panel do you have. I'll give you the best setup.


Also I have a variety of interlock kits, somebody was looking for one, what kind of panel?

 

[roger]

Also I have a variety of interlock kits, somebody was looking for one, what kind of panel?

I need a K-1010 or an equivilant for an ITE , you got one?

Roger

 

[iwire]

This is just what I have been saying from the start, ?a calculation MUST be made.?

No Mike it does not say a calculation must be made, a calculation is one way.

I just don?t think that any code enforcement official will openly make the statement that turning off one circuit in order to turn on another would be an approved calculation.

Again, a calculation or other approved methods, the other approved methods do not have to include any calculations.

I don?t think that over current devices will provide any protection for over revving of a generator which will not only raise the voltage but the frequency.

Nope, an OCPD will not protect against over speed, but I also do do not see over speed as likely, perhaps you meant under speed?

It is not my reasoning it is the verbiage found in 702.5(B) of the 2008 NEC.

We interpret the same section differently, your opinion is as valid as mine.

There is a good founded reason why Article 702 was addressed for the 2008 code cycle and most of it was due to complaints that the monies the homeowner was spending for a generator that wouldn?t work as they had been told it would.

For Automatic transfer means, not manual.

We can understand things we know about such as the overloading of a generator but take some elderly person who has medical equipment plugged in on this little cracker box and has spent their life savings to have it installed and see if they understand that their oxygen has to go in order to make a cup of hot soup in the microwave.
This is one of the primary reasons why the loads MUST be calculated.

And how is that different from that same person plugging in their life safety equipment and say a space heater on the same branch circuit?