article 702.5 help

Status
Not open for further replies.
E

elohr46

Senior Member
Location
square one
The last sentence in article 702.5 "The user of the optional standby system shall be permitted to select the load connected to the system."

Some jouneyman in our shop think that this means that you can connect a 16KW generator to a 200 amp single phase panel in a SFD via automatic transfer switch and only turn on/off the loads that you need at the time of power failure. AC units in the summer or heating equipment in the winter, etc.

I say you need a seperate panel that contain ONLY the loads that the generator is sized to handle, or a generator large enough to handle the connected loads of the 200 amp panel.

Anyone know the CMP's intent on this?
 
elohr46,

If you read the Capacity and Rating of Art. 700, and 701, they state that

the gen. SHALL have capacity for all connected load, but, 702.5, has the

wording a little different, " all equipment intended to be operated at one

time" . Plus how could the user select, if not too much was available? I

don't know the answer, but maybe your workmates are on to something.

With all that said, I'm pretty sure the 2008 NEC will have your mindset.
 
After a couple of trips outside in robe and slippers to reset the breaker, most homeowners learn how to keep from overloading the generator.

It's not that hard to interrupt HVAC 24v wiring to have compressors and heat strips drop out when switching over.
 
Larry, coming from a guy who thinks nothing of venturing into 'electronics' (I'm thinking of some of your LED applications), that's not very comforting. Your definition of "easy" is not the same as most other electricians. ;) :cool:

That said, I agree with what you said, and what Ryan said. The journeyman is correct (until 2008).
 
georgestolz said:
That said, I agree with what you said, and what Ryan said. The journeyman is correct (until 2008).
Click to expand...


With that statement, some jurisdictions may not be on the 2008 NEC until 2014 or even later...

In NY, I can see the state getting to reference the 2008 some time in 2011 or maybe later.
 
I disagree with the change in the 2008 Code. An optional standby system is not intended for the protection of life, or property for that matter, unless chosen to do so at the discretion of the owner. Primarily these systems are installed for convenience. If my optional standby system fails, I am in the same boat with my neighbor who doesn't have a standby system. We can both sit around in the dark and eat vienna sausages. Section 90.1(A) provides that the purpose of the code is "the practical safeguarding of persons or property from hazards arising from the use of electricity". I think the code panelist need to revisit that section every now and then.
 
ryan_618 said:
I agree, I don't like it either.
Click to expand...


Add me to the nay list. As RB outlined this is a system for convenience. IMO the 2008 requirement is going a little too far.
 
I may be wrong, but it seems as though I heard the 2008 change will only affect ATS installations, not MTS installations, although in any case, I don't have a clue as to why this would be an NEC concern.

I have always liked the following post from an old thread.

john m. caloggero said:
The NEC in Section 702.5 that the "optional standby system shall have adequate capacity and rating for the supply of all equipment intended to be operated at the same time." The Code is quite clear in the last sentence of this section that states "The user of the optional standby system shall be permitted to select the load connected to the system." This is quite clear that the AHJ has no jurisdiction over the loads that are going to be supplied.
Click to expand...

Roger
 
Here is what the 2008 will say:

702.5(B) System Capacity. The calculations of load on the standby source shall be made in accordance with Article 220 of by another method that is acceptable to the authority having jurisdiction.
 
Just friggin' great!

I didn't catch this one before :(
Now I have to lobby my AHJ to not adopt this section. Wish me ALOT of luck.

I don't see this change affecting the hundreds of Generac systems from HD and Lowes that are installed in my area by unlicensed, unpremitted contractors.

-end rant.
 
Ty, if the installation is a manual operation there really won't be any change

Report on Proposals A2007
Click to expand...
? Copyright, NFPA NFPA 70

(B) System Capacity. The calculations of load on the standby source shall be made in accordance with Article 220 of by another method that is acceptable to the authority having jurisdiction.

(1) Manual Transfer Equipment. 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. The user of the optional standby system shall be permitted to select the load connected to the system.

(2) Automatic Transfer Equipment. Where automatic transfer equipment is used, an optional standby system comply with a or b.

(a) Full Load. The standby source shall be capable of supplying the full load that is transferred by the automatic transfer equipment.

(b) Load Management. Where a system is employed that will automatically
manage the connected load, the standby source shall have a capacity sufficient to supply the maximum load that will be connected by the load management system.
Click to expand...


Roger
 
Selective reading ...

Selective reading ...

ryan_618 said:
Roger, I have read that 100 times and never caught that it only applies to ATS. Thanks for straightening me out! :)
Click to expand...

Thats OK, my Bride always blames me of selective listening :rolleyes:
 
Status
Not open for further replies.
Top