2020 NEC requirement for outdoor disconnect on 1 or two family dwelling units.

[hornetd]

Is there any hard data on the number of firefighters shocked or electrocuted under these circumstances? Anybody even heard of one?

Turnout gear is pretty damn tough. When you are breaking through a burning wall the last thing that is going to bother you is some live electrical wiring. As soon as you cut it it will trip the breaker anyway.

So as for the Eaton propaganda, the NEC is stupid enough to fall for it but I'm from NY.

-Hal

Hal

In 45 years of front line service as a firefighter I've been shocked several times. My sopping wet fire fighting gloves did not provide any protection at all. The gloves are very resistant to heat or cutting but they are worthless against electric contact. The few times I resorted to pulling a meter were because of basements with standing water in them. I've even been shocked right through my turnout coat when I brushed up against aluminum siding that had been energized by fire impingement damage to the service entry cable. The incident commander saw me flinch and then apply a non contact voltage detector to the siding which lit up and began beeping. I didn't have to say anything to him. As soon as the primary search was completed he had the evacuation signal sounded on apparatus air horns and dispatch repeated the order every minute until accountability was completed. I always thought that chief was sharp but after that I thought he could walk on water.

--
Tom Horne

 

[ggunn]

Has it ever occurred to you that the code is wrong and the process is everywhere from subverted, to corrupted to infiltrated?

To those of us whose designs and installations are subject to rejection and inspection failure by AHJs who are going by the NEC it really doesn't make much difference if the code is right or wrong.

 

[hbiss]

Hal

In 45 years of front line service as a firefighter I've been shocked several times. My sopping wet fire fighting gloves did not provide any protection at all. The gloves are very resistant to heat or cutting but they are worthless against electric contact. The few times I resorted to pulling a meter were because of basements with standing water in them. I've even been shocked right through my turnout coat when I brushed up against aluminum siding that had been energized by fire impingement damage to the service entry cable. The incident commander saw me flinch and then apply a non contact voltage detector to the siding which lit up and began beeping. I didn't have to say anything to him. As soon as the primary search was completed he had the evacuation signal sounded on apparatus air horns and dispatch repeated the order every minute until accountability was completed. I always thought that chief was sharp but after that I thought he could walk on water.

--
Tom Horne

This is the kind of real world feedback we need to hear. Thanks!

-Hal

 

[jim dungar]

... aluminum siding that had been energized by fire impingement damage to the service entry cable. ...

Depending on the placement of the proposed service disconnect, this type of situation could still exist.

 

[romex jockey]

Jesus Tom, and i felt like a dinosaur when they gave me the gold watch @ 30 yrs

My helmet's off to you.....

~RJ~

 

[LPS]

For exterior disconnects on residential I use the Square D QOM2 enclosure with appropriately sized breaker, and a main-lug loadcenter inside.

Any supply house around you should have something similar as there are many installs that currently require a disconnect.


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LOL... I haven't looked at this since I posted it many months ago. Seems like I started quite a dumpster fire.. So please allow me to toss in some gasoline

1. I don't know why it's such a big deal. If it says install a disconnect, install it...

2. We are all required to provide safety training for our employees, and the first thing you explain is the general duty clause:

The OSHA general duty clause, Section 5(a)(1) of the Occupational Safety and Health Act, requires that each employer furnish to each of its employees a workplace that is free from recognized hazards that are causing or likely to cause death or serious physical harm.

The most important part of providing a safe workplace is training. When training electricians the first thing you explain is the general duty clause above, then the rest of the safety training mostly boils down to not working things hot. Without exception, the very first negative response is "Then, how do you work in a residential panel?". For me, this helps resolve the apparent conflict between NFPA-70 and 70E.

And, brantmacga, thanks for answering my question....

 

[kwired]

Hal

I served 45 year as a Firefighter EMT. Every riding position on the apparatus had assigned initial duties to perform. Barring situations were the unit's Officer In Charge (OIC) has to redirect the firefighters on the unit to a more urgent task, one of the default assigned roles is Utility Control. That includes shutting off any outside liquid or gaseous fuel source and opening the main breaker of the service equipment. The Utility Control Firefighter also searches the floor were the Service Equipment is located as soon as the Power was shut off. When that firefighter dismounted they already had a hydraulic lock breaker (Hydra Ram), Irons; this is a flat head axe and a "Halligan bar" prying tool; and the short bolt cutters in order to be able to force entry into the portion of the structure were the utility controls were located. I filled that role many times because the officers trusted me to know what the main disconnect is since I was a working electrician.

Therein lay the source of my antipathy to what the Fire Investigators wanted us to do. The always harped on only opening the Main Breaker so as not to disturb a tripped breaker which might help determine the "Cause and Origin" of the initial ignition. I kept pushing right back at them saying that what made up the Service Disconnecting Means is often less obvious than they assumed. I wanted the Utility Control Firefighter to open every single disconnect and circuit breaker that they could find. A smoke filled basement with low visibility is no place to try to figure out which breakers were the "Main."

The housing stock in our service demand area; which firefighters call their "First Due Area;" was mostly older than 50 years. We have a lot of fused pullouts as the Service Disconnecting Means and far more split bus panels than a newer built area would have. We even have a fair number of Sears, Roebuck and Company kit homes with the numbering on the structural lumber still visible in the basements and attics. Most of those are still wired with knob and tube. Some of the panels in our first due area were assembled from parts into a cabinet that had been made by the carpenters. The electricians would then line them with asbestos sheeting and build the panel board inside that cabinet. We also have some converted DC trolley power 600 volt panels which have fuses in all of the neutrals. Keep in mind that there is no legally enforceable mechanism to force any of the owners to upgrade these relics from the dawn of electrical use in dwellings.

On the one hand I like the idea of an external disconnect of some kind for the safety of Firefighters. But it will take many decades for the existing houses to be replaced or modified sufficiently to force the electrical to be brought up to present code. On the other hand our area has had a steady growth in Home Invasion robberies and I can understand the concerns occupants have about having an electrical disconnect outside of the home.

The region's telephone service provider convinced the Public Service Commission to remove the requirement for the telephone Customer Service Unit to have battery backup with the batteries maintained by the service provider. They do not even have to provide the initial back up battery now. Since the provider is now changing all service to fiber optic lines, loss of utility power cuts off telephone service to all affected premises. So you want to invade a home and hold the spouse and or children hostage so that the other spouse will withdraw the family's life savings and give it to the robbers step one is to cut off the power to disable the fiber optic telephone service and make the occupants come outside to restore power.

I sure hope that a power outage is not caused by, say, an ice storm which destroys the antennas on most cell towers and pulls down all of the aerial fiber which connects them to the Public Switched Telephone Network. Ice Storms are the most frequently occurring weather disasters in this region.

[/RANT] = Rant mode off.

--
Tom Horne

I can understand it being simpler for fire fighters to have such an outside disconnect, and even agree that some older installs already have an outside disconnect that meets the new code requirement (other than new labeling requirements that apply to it).

But why does it just apply to one and two family dwellings? Seems there are many more non dwelling applications out there that even though met NEC code when installed are more complex when it comes to assuring you have disconnected everything than is typical for a one or two family dwelling. How about a large facility that has legal multiple services that are not in same location? Signs were required, but still makes it harder for those fire fighters when they want to kill all the power to the facililty. Now you need to know the layout of the facility to find those additional service disconnecting means even if they are well marked and other locations are given in the signage.

 

[shortcircuit2]

Well there are a lot more 1 and 2 family dwellings. Code may add the others in 2023...

Shunt trip could be allowed for over 400-amp....with the service in a 2-hour room or closet.

 

[kwired]

Well there are a lot more 1 and 2 family dwellings. Code may add the others in 2023...

Shunt trip could be allowed for over 400-amp....with the service in a 2-hour room or closet.

True but finding the service disconnecting means isn't necessarily as much of a challenge in a majority of them as it might be in some non dwellings.
Look for meter, a majority of time if disconnect is not at the meter it is about directly behind it inside or maybe directly behind but down in a basement, raceway leaving that meter and entering the structure is also a clue. Similar clues often work on small capacity non dwellings. but large capacity non dwelling may have underground feeds that are still considered outside the building if they run under a slab and emerge somewhere in the middle of the building. Not that I haven't done that on a house before (my own is that way) but is still easier to find it in a 1000 square foot or less bottom floor than to have to search a 50,000 square foot plant for the main disconnect(s).

 

[jap]

I had a fellow electrician install a 400 amp combo meter main house panel with (2) 200 amp mains in it.

The inspector in that area failed it and is requiring him to install a single 400 amp disconnect ahead of the combo meter main for a single disconnecting means.

What exactly is the new rule?
Are they doing away with the 6 movement rule all together and trying to get to a single main disconnect in 1 and 2 family dwelling units?

This surprised me.

JAP>

 

[ActionDave]

I had a fellow electrician install a 400 amp combo meter main house panel with (2) 200 amp mains in it.

The inspector in that area failed it and is requiring him to install a single 400 amp disconnect ahead of the combo meter main for a single disconnecting means.

What exactly is the new rule?
Are they doing away with the 6 movement rule all together and trying to get to a single main disconnect in 1 and 2 family dwelling units?

This surprised me.

JAP>

The six disconnect rule as we know it is gone.

 

[kwired]

I had a fellow electrician install a 400 amp combo meter main house panel with (2) 200 amp mains in it.

The inspector in that area failed it and is requiring him to install a single 400 amp disconnect ahead of the combo meter main for a single disconnecting means.

What exactly is the new rule?
Are they doing away with the 6 movement rule all together and trying to get to a single main disconnect in 1 and 2 family dwelling units?

This surprised me.

JAP>

The six disconnect rule as we know it is gone.

No it is still there, some conditions are what has changed. Main thing that is gone is you can not have multiple service disconnecting means in same panelboard or same section of a switchboard. You can still have six disconnects in six separate enclosures or six disconnects in six different vertical sections of switchboard or in six different compartments in meter centers See 230.71(B).

Problem with the typical combo meter/with 2-200 amp mains that many have been using for long time on 400 amp residential services is the two mains in same compartment doesn't comply with the new rules. I kind of anticipate there will either be code change in future that will allow this particular setup or the equipment will eventually be modified so that the two mains are no longer in the same compartment. But for now you probably going to have to settle for using a separate meter cabinet and two 200 amp enclosed circuit breakers on outside of house in most those situations.

 

[ActionDave]

No it is still there, some conditions are what has changed. Main thing that is gone is you can not have multiple service disconnecting means in same panelboard or same section of a switchboard. You can still have six disconnects in six separate enclosures or six disconnects in six different vertical sections of switchboard or in six different compartments in meter centers See 230.71(B).

Problem with the typical combo meter/with 2-200 amp mains that many have been using for long time on 400 amp residential services is the two mains in same compartment doesn't comply with the new rules. I kind of anticipate there will either be code change in future that will allow this particular setup or the equipment will eventually be modified so that the two mains are no longer in the same compartment. But for now you probably going to have to settle for using a separate meter cabinet and two 200 amp enclosed circuit breakers on outside of house in most those situations.

Ok.

The six disconnect rule as we know it is gone.



Agree or disagree?

 

[kwired]

Ok.

The six disconnect rule as we know it is gone.



Agree or disagree?

You are still allowed six disconnects. However they can no longer be all in one panelboard and must be in separate vertical sections with barriers between them of switchboards.

You can still have six individual fused disconnects or individual enclosed circuit breakers as your service disconnecting means.

The main goal here I believe is they don't want you to have exposed live bus or other live terminals when working with just one of those disconnecting means. The more recently required line side barriers on a single main apparently is acceptable though. Canada I'm pretty sure they have for many years required an additional metal shield over the supply conductors so there is nothing live inside with the main off and the regular cover removed.

 

[jusme123]

I actually agree with the outside disconnect requirement , it should have been a requirement 20-30 years ago. The disconnect should also be integral to the meter assemble

 

[kwired]

I actually agree with the outside disconnect requirement , it should have been a requirement 20-30 years ago. The disconnect should also be integral to the meter assemble

I can understand requiring it to be outside, but why require it to be integral to meter assembly? Might look nicer but doesn't have much impact on safety.

 

[brantmacga]

I actually agree with the outside disconnect requirement , it should have been a requirement 20-30 years ago. The disconnect should also be integral to the meter assemble

I disagree on both.

I disagree about integral meter main combos, and I do not use them on single family dwellings at all. My reasoning is, if a jaw melts down in the meter base (which I’ve seen dozens of times, fixed one last week actually), and it’s a utility meter base, they’ll usually have some parts on the truck or will go get the parts to replace the internals for the customer. If it’s an integral meter main, the customer is SOL. And it never happens mid day. It’s always at night or on a weekend.


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[tom baker]

I have installed equipment in damp areas and used low wattage strip heaters with T stat set at 60 DF. Eliminated condensation. For a NEMA 3R panel may not work as they are not very tight air wise

 

[ZZZ]

Didn't mean to "irk" anyone... Just thought I'd have at least one example of what the students will be seeing soon. According to Ryan Jackson this has been required in other states for quite some time, including his state of Utah (I think it was Utah). He mentioned many people will find this to be a major change, but it's perfectly normal where he's from. I'm hoping to get feedback from people in those states.

How dare you "irk" someone by teaching future electricians the code that will be current before they finish their apprenticeship? You should teach them some old, obsolete code, and let them make their own screwups like everyone else. LOL

 

[McLectric]

This kind of stuff irks me no end. As soon as a new code cycle is even mentioned instructors go woah, I need teach to it. You are on the the 2014 NEC AS AMENDED. How about focusing on making your class proficient with that code instead of confusing them with something they may not see until years from now if ever? Geeze, some states are still on the 2008. I'm on the 14. I couldn't care less about the 17 and I'll probably be retired before the 20.

As to your question, pretty much the same principle applies. Don't expect suppliers and manufacturers to gear up with this stuff when demand for it might be 5 years from now, if ever.

In my state of Massachusetts 2020 went into effect 1-1-20.