Panel height, min max?

[hurk27]

Not sure about in other areas of the country but here in Indiana we don't classify a garage at a dwelling as the intention is only for the purpose of parking of personal vehicles and not for working on them, also many insurance company's will not cover the damage from a fire cause from working on a vehicle in a attached garage to a dwelling, this is also why here we don't require a fire wall between the garage and the dwelling, Indiana also treats a detached garage the same as far as code goes, but doesn't require any electric to it, but if you do install any electric then the normal codes do apply.

So before you preform any work on a vehicle in a attached garage to a dwelling make sure you check with your insurance company first, we have had several who have lost their homes not knowing this, and got nothing from their insurance because they didn't know that their policy did not cover preforming work on a vehicle in a attached garage.

 

[gndrod]

No single one in particular.


If the area is not classified then none of those sections apply.

There are sections that do classify the area up to 18" above floor, in those places you could still have a panelboard within 18 inches of the floor, but the panelboard would have to be rated for the classified area making it much more expensive than using a so called general purpose panelboard and keeping it out of the classified area.

A quote from the Article-Section for substantiation is what was really in question. There is the minimum 18" AFF distance requirement I quoted for code compliance in residential.

There is a good reason why water heater heights in a garage are 18" AFF as are all electrical boxes that are considered spark source devices. Note that parking garages shall be permitted to be "unclassified". [511.3(A)]

 

[kwired]

A quote from the Article-Section for substantiation is what was really in question. There is the minimum 18" AFF distance requirement I quoted for code compliance in residential.

There is a good reason why water heater heights in a garage are 18" AFF as are all electrical boxes that are considered spark source devices. Note that parking garages shall be permitted to be "unclassified". [511.3(A)]

There is good reason because the area is classified. Note the 511 reference you mentioned is for commercial garages. Very few other 'garages' will have this area classified.

You also are not prohibited to put electrical equipment in this space, it just has to be equipment rated for the classification if you do put it there.

 

[gndrod]

There is good reason because the area is classified. Note the 511 reference you mentioned is for commercial garages. Very few other 'garages' will have this area classified.

You also are not prohibited to put electrical equipment in this space, it just has to be equipment rated for the classification if you do put it there.

Thank you and I agree to classified hazardous areas relative to the NEC 500-517. The post made concerning the 18" AFF originally is related to other trade codes (I.e. UPC,UMC, UBC) where new IRC references not mentioned in the NEC can resolve why our dialogs are not in agreement where residential garages are concerned.

The multiple plumbing, mechanical, and building trade code references in the IRC specifically state the minimum 18" height requirements regardless of the NEC 500-517 "classified" permissions and constraints. A good example is the reason for water heater heights can be cited in IRC P2801.6. as stated:
"Water heaters having an ignition source shall be elevated such that the source of ignition is not less than 18 inches (457 mm) above the garage floor."

All is meant well and I see where your expertise is coming from.

 

[hurk27]

Never understood why we classify these areas but have no problem driving a vehicle into these areas which sits low to the floor?:happysad:

 

[kwired]

Never understood why we classify these areas but have no problem driving a vehicle into these areas which sits low to the floor?:happysad:

Or all the welding, grinding and other spark producing activity that often goes on in these places.

I think the primary purpose is to prevent gases from migrating through raceways if they are present.

 

[hurk27]

Or all the welding, grinding and other spark producing activity that often goes on in these places.

I think the primary purpose is to prevent gases from migrating through raceways if they are present.

Not so sure of that, because one, natural and propane gases are heavier then air, the reason for the 18" requirement is because they will accumulate at the floor so to keep the ignition source above this accumulation, if conduit is coming into the area from above the gas, it can not go up it unless there is a negative pressure in another area the pipe runs to or a positive pressure in the garage that would push the gas up the pipe, its been code for a while now that forced air HVAC systems have to be kept separate from the dwellings HVAC systems to not only prevent this type of problem but to also keep from causing carbon monoxide from a vehicle left running from being drawn into the dwelling via a difference of pressure.

Why 18" was the magic distance I am not sure of, but also most garage floors are required to be sloped at about 4" from rear to the overhead door opening or there must be a 6" high barrier wall or landing put around any stairs leading down to a basement all required when there is gas appliances in a garage.

This is off the top of my head as I remember it from many state meetings so some of it might not be totally right.

Here because of the cold its rare to find a water heater in a garage, but there are some.

But now I ask this question, Why are these requirements just for garages? why not when a gas appliance is installed in a house in a closet or utility room? or was this requirement made more for the gasoline in vehicles and not because of the appliance? I'm not sure?

Looks like I have something to look up

 

[kwired]

Not so sure of that, because one, natural and propane gases are heavier then air, the reason for the 18" requirement is because they will accumulate at the floor so to keep the ignition source above this accumulation, if conduit is coming into the area from above the gas, it can not go up it unless there is a negative pressure in another area the pipe runs to or a positive pressure in the garage that would push the gas up the pipe, its been code for a while now that forced air HVAC systems have to be kept separate from the dwellings HVAC systems to not only prevent this type of problem but to also keep from causing carbon monoxide from a vehicle left running from being drawn into the dwelling via a difference of pressure.

Why 18" was the magic distance I am not sure of, but also most garage floors are required to be sloped at about 4" from rear to the overhead door opening or there must be a 6" high barrier wall or landing put around any stairs leading down to a basement all required when there is gas appliances in a garage.

This is off the top of my head as I remember it from many state meetings so some of it might not be totally right.

Here because of the cold its rare to find a water heater in a garage, but there are some.

But now I ask this question, Why are these requirements just for garages? why not when a gas appliance is installed in a house in a closet or utility room? or was this requirement made more for the gasoline in vehicles and not because of the appliance? I'm not sure?

Looks like I have something to look up

I still think it is mostly for preventing migration through raceways. True if the gas is a heavy gas it will just sit in there but at some point there is going to be a pressure difference and then it can move to other areas. Sealing fittings are required at the classified area boundary because of this in all classified areas. Most commercial garages the general rule is don't put any electrical below 18". It is not because you are not allowed it is because of why mess with needing art 500 methods here if you can avoid them altogether?

I don't know anything about rules for water heaters in residential garages and other similarities. I am primarily talking commercial garages. The area up to 18" is determined to be classified. That may be excessive in some places and may not be enough in others. I think commercial garages are the only place this area is classified like that because it is expected there will be gasoline leaks or spills at times where as in a residential garage or parking garage it is mostly incidental and not a regular event.

Just my $.02 worth of information.