it doesn't unless your electrical service is serving a number of tenants.

Can you tell me where I can read it. I
did some reading after posting this and seems like it depends on the amperage of the service and how service brought to the building. Like if service brought underground, then the room could be located insside the building. The code doesn't like when conduits are too long before they enter electrical room from exterior.

Call a local electrical engineer

where do you live? i would just call the building department and ask them. they can usually cite any passage.

You can cut down on interior corridor space.

call the city because no matter what the code there will be other criteria like from the fire chief.

What type of building is it? If its a multitenant retail than outside but i dont think they ever not let you have exterior access, even an office building for switchgear.

also specific criteria from the utility co.

Thank you for responces

It is a metal building, most likely slab on ngrade; single tenant vehicle maintenance facility. There will be high electrical loads. And we are doing pre-conceptual design, no consultants yet.

if memory serves you have an F-1 MOderate Hazard Occupancy Classification. I would call the city to find out what you may need.

i don't recall a specific requirement to be accessible from the exterior. typically they're located on an exterior wall so they can replace switchgear without having to worry about how to get those behemoths through a building.

i do recall that 1200 amps requires 2 exits though...

... is that cause if you're electrocuted, they need a secondary entrance in case your bbq'ed carcass is blocking the primary entrance?

actually that happened recently at purdue. some student went into an electrical room and i guess fell into a transformer and was electrocuted. he was missing for a month before they found his body.

well they gotta give you some chance...

side note - i was working on a project at an abandoned shopping center recently, and naturally someone had stolen all of the copper feeds.

the scary part is that they got greedy and must have shorted a secondary coming out of the pad mounted transformer that fed the MDP about 5 feet away. the MDP had a hole blown/melted in the panel about 12" diameter.

must've scared the shit outta whoever did that, if they remember.

"it doesn't unless your electrical service is serving a number of tenants."

wrong. i've done this a million times and you don't need an exterior access. you need to worry about clearances in electrical rooms. if you're clearances are per code, then you will only need 1 or 2 doors depending on equipment voltage. transformer dry vaults are different. you need to provide exterior access for the utility company.

1200 amps do not require 2 exits if you double the required clearance. so if you have 7 feet in front of a 1200 amp switchboard, then you only need one exit.