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

[George Stolz]

My 2008's in the truck, and it's raining, so hopefully the '05 is the same, give or take...

1.) NEC Section/Paragraph: 230.70(A)(1)

2.) Proposal/Comment Recommends: [deleted text]

3.) Proposal/Comment: (1) Readily Accessible Location. The service disconnecting means shall be installed at a readily accessible location either outside of a building or structure or inside nearest the point of entrance of the service conductors.

(Red text deleted)

4.) Substantiation: Allowing service equipment indoors poses an unnecessary risk to personnel and property, usually for asthetic reasons. Services supplied by raceway wiring methods provide pathways into a structure for both arc blast events contained in the laterals themselves as well as outdoor tranformer explosions.

Attached are two events that occurred within a month of each other, within 20 miles of each other. In both events, there were personnel present who could have been seriously injured by the explosions and subsequent fires from service lateral and outdoor transformer faults.

Source: Bank Fire, Fort Collins, CO

An electrical fire Monday morning at the Wells Fargo Bank located at 3500 John F. Kennedy Parkway has closed the bank for an undetermined amount of time.
The fire was caused when a concrete boring machine came in contact with a high voltage underground electric line going into the building. A utility contractor was working at the property at the time, said PFA Assistant Fire Marshal Holger Durre.
Poudre Fire Authority responded to the fire at 11:52 a.m. with five fire engines and had the flames contained within 15 minutes of arriving on the scene.
The first crews found fire coming from a transformer on the exterior of the building. Smoke had also filled the basement of the building.
There were no injuries in the fire, although PFA Assistant Fire Marshal Shawn Brann said one person was trapped in an elevator because electricity was cut to the building.
Mardene Abarbanell, a Fort Collins resident who banks with Wells Fargo, said she was in the bank when the fire started. She said there was a loud explosion that caused the building to shake and that sounded like it came from the roof.
"It was just the most frightening thing I've ever experienced," she said. "My first thought was it sounded like an airplane had hit the roof because the building shimmied."

Source: Good Samaritan Fire, Windsor, CO

According to fire chief Brian Martens, the first occurred around 7 a.m. Tuesday when a padmount electrical transformer at the Good Samaritan Society, Water Valley Resort, under construction, started on fire after a construction worker contacted it with a construction lift, short circuiting the transformer.

The fire was further hindered when gas built up in conduit that leads to the electrical room exploded.

Structural damage to Good Samaritan facility was contained in the electrical room with some wall damage, Martens said.

It took firefighters about 90 minutes to extinguish the fire, which was ruled accidental.

In the Windsor event, there was an electrician inside the described electrical room minutes before the electrical equipment inside the room exploded, literally off the walls they were mounted to. He was reacting to the transformer accident outside, shutting down electrical equipment inside the building to isolate the premises wiring system from the utility. If he had lingered in the room he would be dead.

There is no reason to allow deadly equipment to be installed inside a building for asthetic reasons.

(end)

This ought to spur a discussion...

 

[Buck Parrish]

There is no reason to allow deadly equipment to be installed inside a building for asthetic reasons.

(end)

This ought to spur a discussion...

I can't see a way around it. The equipment needs to be kept dry. And free of squirells and snakes, etc...
You could use some type of relays. But it would have to be built in to the main equipment breakers .

 

[George Stolz]

I can't see a way around it. The equipment needs to be kept dry. And free of squirells and snakes, etc...
You could use some type of relays. But it would have to be built in to the main equipment breakers .

Services are installed outside every day, using NEMA-3R rated equipment.

 

[mdshunk]

Services are installed outside every day, using NEMA-3R rated equipment.

Yeah, but you really don't have a good concept of how big service equipment can be or get. It can certainly fill hundreds of square feet. Probably more.

 

[Buck Parrish]

Services are installed outside every day, using NEMA-3R rated equipment.

I am thinking the hazzardous ones, are equipment rooms. With lots of switch gears, etc...

 

[augie47]

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.

just a thought.

 

[JohnE]

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?

 

[Dennis Alwon]

FWIW, I like the idea....

 

[SiddMartin]

If what ur saying is "Putting the Main disconnect on the outside and everything else can be inside." I can live with that.

 

[George Stolz]

That is what I'm saying.

And I know it's a little outside the box. Had a few beers with a friend last night, figured it would make an interesting proposal/discussion.

 

[SiddMartin]

All you have to do is put a disconnect outside, now, granted I havn't installed a service larger then 800A, but what your saying is do-able. Were not talking about putting ALL the equipment outside

 

[Buck Parrish]

If what ur saying is "Putting the Main disconnect on the outside and everything else can be inside." I can live with that.

Some buildings require so much power. The disconnects by NEC Standards would be the size of a dump truck.
On the other hand the poco can turn it off with a 15 ft. fiberglass stick.

 

[SiddMartin]

Some buildings require so much power. The disconnects by NEC Standards would be the size of a dump truck.
On the other hand the poco can turn it off with a 15 ft. fiberglass stick.

I would agree with that. The situations I agree with the OP is only what I have experienced, (up to 800A), so, dont' go off just what I say:smile:

 

[C3PO]

Don't some POCO's already require this?

 

[cadpoint]

OK, No, I don't agree, this would kill the SOP of whats near standard or any future installs of large service from a POCO controlled lateral point.

I'm working a job right now where the need for a large disconnect was elimited outside because the direct underground service will still be controlled and protected by the POCO throught to a gutter thats inside the building.

There's alot of mini substations sitting outside plants direct to a MCB.

 

[ceknight]

And I know it's a little outside the box. Had a few beers with a friend last night, figured it would make an interesting proposal/discussion.

Lemme guess, Ron put you up to this? Troublemaker.

From the examples you cited, maybe a better remedy would be to ban conduits from pad-mounted transformers into the buildings they serve, regardless of whether there's a service disconnect located outside. It'd be much safer just to lay some SE on the ground.

 

[Buck Parrish]

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.

 

[e57]

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.

just a thought.

I agree 100%! FYI - you forgot rust for coastal areas - and a comfy chair in an air conditioned room inside. Heat is also 'horrific weather' as well IMO.

I believe the rules as currently set up could even be relaxed as far as distance inside - by taking all discretion from the AHJ all together, and imposing no limit at all.

But maybe - beef up raceway to only RMC +/or encasement etc. for 50' or <. (My poco only allows RMC inside or out anyway...)

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. No terminations would make it need only be accessible - not work-space. The alarm could even be powered solely by fault current???? The alarm could then travel in a different seperate conduit for shunt trip of the OCP, and be monitored by a FCP if necessary.

 

[e57]

Some buildings require so much power. The disconnects by NEC Standards would be the size of a dump truck.
On the other hand the poco can turn it off with a 15 ft. fiberglass stick.

Ironic that I just got done watching my local poco out my front window do that with the 11kv switch in the vault out in the street for the water res. down the block. He also did his version of LOTO and put a tie wire tag on the switch with a hot stick 20' down in the street - impressive...

 

[iwire]

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

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.