230.70(A)(1) - No services inside a building

[electricmanscott]

Based on the fact that there are gazillions of installations where the service is NOT outside the dwelling and they are fine I'd say leave well enough alone.

 

[George Stolz]

Yeah, but you really don't have a good concept of how big service equipment can be or get.

I guess I don't. How large is the largest (physical and ampacity) indoor or outdoor service disconnect for 480V? Pick a manufacturer.

It can certainly fill hundreds of square feet. Probably more.

Generally speaking, the larger the service, the larger the building it serves. Therefore, a larger lot is available. It stands to reason that therefore, there would be more space for a larger footprint of equipment outside.

George, from a regional standpoint..
what about some areas that are subject to high snowdrifts..are you not possibly better off to have a service disconnect inside, than buried ?
or areas prone to horrific weather.. tornados/ lightning storms..
I rather take my chances and have inside access.

But Gus, outdoor disconnects are not prohibited. Turning your reasoning around, do you think outdoor service disconnects are dangerous enough to be banned?

Are outdoor locations not subject to an arc blast? If the same worker were near an outdoor disconnect, how would he have been any safer?

Good point. However, the main reason for the existing rules are to restrict the presence of them inside, due to the fire hazard they represent. With the larger commercial services, raceways do become pathways for remote arc blasts and transformer oil. Why allow an accident with a utility transformer to jeopardize the equipment/people inside the building?

FWIW, I like the idea....

I'm not sure I do.

See, I'll argue with everybody.

Probably hitting the character limit on this post, so I'll continue...

 

[e57]

Generally speaking, the larger the service, the larger the building it serves. Therefore, a larger lot is available. It stands to reason that therefore, there would be more space for a larger footprint of equipment outside.

Not in my town - where buildings are lot line to lot line. Little or no set backs.

 

[George Stolz]

Even with an 800 amp service you can mount the panel 50ft. on the interior of the building with no disconnect outside.
Because the feeders come from under the concrete which is considered outside. This eliminates that exspensive disco.

I'm not quite sure what you're saying - the proposal is intended to stop that.

But maybe - beef up raceway to only RMC +/or encasement etc. for 50' or <.

The fault at Wells Fargo burned through a piece of RMC, if I recall correctly. I wasn't on site, but I got a chance to see what was left of the service sitting in the shop parking lot. But even if it hadn't, the intact RMC serves as a sort of pipe bomb if the conditions are right. The barrel of a gun is very solid, and the projectile out the end moves very fast.

And/or make a device neccesary to sense ground or phase-phase faults prior to entering past a certain distance like 50'. 50' or > would require a device to sense a fault and sound an alarm. The device (not a disconnect) could be out in a chisty box near the street or in a small enclosure or pull box. All it would need to have in it would be split-core CT's - no terminations would be necessary - and a seperate conduit to an alarm if a fault occured.

Suppose the service were disconnected. How would this stop a lateral fault from exploding along the raceway into the building?

Based on the fact that there are gazillions of installations where the service is NOT outside the dwelling and they are fine I'd say leave well enough alone.

I bet if I were to look harder than just for the two I knew about, I'd find a lot more that are not fine, and caused thousands (maybe more?) in damage. Maybe even a body count. At what point does it become a valid concern?

I can't see requiring all service disconnecting means to be outside.

I can't say I expected it to be a popular idea.

However how about a requirement for a remote disconnecting means at an accessible location for other then single family dwelling units?

In this area it is not an unusual requirement of the fire dept to install a shut trip button in location easily accessible by firefighters. Often this will be near the fire panel or fire panel remote annunciator.

Some have even required buttons at the fire panel to shunt the generators and UPS systems. I think it makes good sense.

My main thought is, it won't stop the damage that can get into the building from someone tapping a utility transformer with a boom lift, which is the main idea I'm advancing with this.

Many thanks for all the replies, keep 'em coming!

 

[iwire]

Generally speaking, the larger the service, the larger the building it serves. Therefore, a larger lot is available. It stands to reason that therefore, there would be more space for a larger footprint of equipment outside.

Typical Boston neighborhood.

Often designated 'Historic' that means the service can not go on the front side and very often for privacy and security the rear is made inaccessible without passing through the home.

Here is a row of five buildings in Boston, the back side is also a sidewalk and city street.

Kind of tough finding room for service disconnecting means.

 

[ceknight]

Kind of tough finding room for service disconnecting means.

It's Boston. Just put it out in the street, none of the drivers will care.

 

[e57]

The fault at Wells Fargo burned through a piece of RMC, if I recall correctly. I wasn't on site, but I got a chance to see what was left of the service sitting in the shop parking lot. But even if it hadn't, the intact RMC serves as a sort of pipe bomb if the conditions are right. The barrel of a gun is very solid, and the projectile out the end moves very fast.

Suppose the service were disconnected. How would this stop a lateral fault from exploding along the raceway into the building?

No RMC would not stop a fault - but as your op implied would make it 'safer' from those accidently damaging it - than say NMC on a cold day, or SE cable in any weather, or a nail or screw in a wall... Encasement would even be better - and already in the code for certain situations at the descetion of the AHJ....

And my mention of an alarm would not stop the service from a fault - but would aid the responce time of Fire/EMS and poco for full disconnection and remedy of the problem. As well as alerting those in thebuilding to the immediat threat of harm....