exterior main disconnect

this is on a new renovation of a small music school.
why would the main disconnect be only accessible from the exterior of the building?
how is it protected from vandalism?


Main Panel.jpg

MTM Disc & Meter.jpg

I have seen many exterior mains, mostly in the southern or dry climates. Very few of them have been locked but those that were, had a padlock through the hole in the tab that holds the cover closed. I don’t think many people even think about securing their panels.

If a fire starts inside of the building, one of 1st thing a fireman will do is cut the power to the building. If you locate the main disconnect in an inaccessible area or padlock it, you’re creating more of a hazard.

There is a discussion on as we speak on the Fl IAEI BB about a townhouse with several separate units and all the disconnects are grouped on one end of the first one (on his property).
They are not finding a code reason why this is illegal.

Greg, can the other residents get to their discos or is there a fence? I am upgrading eight duplexes, each duplex has the discos in one of the back yards. The AHJ will not allow the new services in that location, citing 240.24(B). Even if the gates are not locked, they are still saying no, we must re locate all of them.

By the way, here in AZ you would be hard pressed to find a disco indoors. Most homes also have all the branch breakers outdoors.

I do NOT see an interior main disconnect as any more of a hazard than many other common things.
The ONLY thing it does is create an easy way for firemen to kill power in an emergency.
I know it is common in other climates, but it is only done in most parts of the country if the code demands it; such as a main panel located well into the structure.

I personally think branch breakers located outdoors to be ludicrous.

Brian, I agree with you. We are in the minority

A very hearty agreement here. It’s so hard on the equipment. I know that in FL and the southwest, it’s common. When you put your branch panel outdoors in the northeast or the mid-atlantic, you’re lucky to get 15 years of service life. I sorta like the idea of an outdoor main disconnect, and try to upsell them, but I generally only install them if I have to (due to distance from the panel).

In our dry desert climate an outdoor service can easily last 50 or more years. I have opened up FPE’s from the seventies located outdoors and they are pristine. Only if the cover gets comprimised or a KO is missing, allowing unwanted guests, does a panel suffer. There are many things we get to do different here from you northerners, we don’t even get frozen ground, ever.

Why do you think the Air Force stores it’s surplus aircraft here? We have acres of them.

O.K. folks,
It makes no sense whatsoever to have the panel box “outside”. Being a newby here in AZ from upstate NY its stupid for many reasons to have it exposed. Did an inspect. yesterday.... cover tight, no missing knockouts but plenty of mouse droppings. Dont know about AZ mice, but in NY they chew EVERYTHING. Maybe they`re more selective here!

Next you will be telling us how to make Salsa. :wink:
Welcome to the west John. :smiley:

I suppose that explains the popularity of plastic panels.
They are most common on piling houses at the beach. The FD likes the disconnect at ground level.

In 6½ years of inspecting in San Diego, as well as 7 years of property renovations, I have yet to find a disconnect and/or a main panel that is not on the exterior of the building. Some of my re-location Clients from Boston and other points north and northeast have been incredulous, but the only answer I can get from electricians is that the fireman’s union demanded it many, many decades ago. Now it’s been entrenched in building practices for so long that no one questions it except for the people wanting a security system, and for that, the security company installs a battery backup in case someone access the electric panel.

Interestingly, San Diego Gas & Electric, does not recommend locking the electric panel, stating that circuit breakers should be readily accessible for use in an emergency, and they don’t consider a lock with a lost key to be readily accessible. I agree with them. I can’t tell you how many inspections I’ve done where the seller/owner/Realtor had no idea where the key was. In fact, some people didn’t even know that their electric panel was locked. I guess none of them ever had an electrical emergency, and that’s good.

i understand the f.d. wanting to the exterior disconnect.
unfortunately at the music school the meter & disconnect are about 5’ above grade. this is directly under a metal roof with about an 8 pitch. it is on a side of the building away from the main or rear entrances. unless maintained, it will be under snow for most of the winter.

yes, i will recommend the maintenance, but then there’s the reality & ultimately the fd could loose worse from what the intended gain was supposed to be. :frowning:

The So Cal, Az and some southeast guys think the outside main is the only way to go for “safety”.
We know that the rest of the country has it’s own reasons against it.

I do, but then againt I don’t.

When I worked as a volunteer with the Fire Department in Houston, the station manager simply called the power company and told them to shut down power to the address. Usually that meant shutting down power to a whole block or two, which was definitely okay since sometimes fires spread to additional structures. Shut down power, fight fire, ask questions later. And I can promise you that SDG&E can shut power down to whatever block they want to at any time.

99% of the homes in CA have their service disconnect on the exterior. It’s the way of the West.