1 & 2 Family Dwellings Emergency Disconnects; Again.

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hornetd

Senior Member
Location
Maryland
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Journeyman Electrician, Retired
When each of our jurisdictions adopts the 2022 edition of the NEC if we alter the service equipment we will have to add the required emergency disconnect. I'm willing to bet that many of you have seen a meter enclosure which is installed as close to the ground as the US National Electric Code (NEC) and the Utility Service Standards allow. That leaves no room to put the emergency disconnect in line after the meter without getting into the expense and time of end to end LR or LL condulets and so forth. It seams some of the utilities are scrambling to negate the language in the 2022 NEC which allows that disconnect to be on the supply side of the meter.

So I go to install an as yet not required emergency disconnect on a home with a developmentally arrested adult child because getting that 22 year old 3 year old out of the building during an emergency is already going to be tough enough for the local fire department without worrying about electric shock. Inspector says "You cannot have a disconnect before the meter." I said "That cannot be possible because over half of the multiple family units in the county have just that. He says "it's not acceptable to the utility." Running out of patience but wanting to go the 62 miles and 1 hour + home to my own bed I say "You mean they have the county inspectors enforcing their service standards now?" while looking all shocked and amazed. He says "No but it's your problem when they refuse connection. I go home and to sleep. I get a call a week later from the utility's engineering office which after mutual introductions goes "About this house out on XXXXXXXXX Road. Me "Yes what about it." Engineer; "We don't like having a disconnect of any kind ahead of our meter." Me; I'll have to justify the additional work with the habitat people so I'll need chapter and verse from the (State Regulator) approved Service Standard." 30 seconds of silence follows. Engineer "That's pending approval" Me "I have a permit that is signed off as final inspection approved and ready for energizing." Another 30 seconds of silence. Engineer "Were going to ask that it be changed to comply with the service standard when it gets approved." Me "you can ask for anything of course but your legal department will tell you that no regulation approved after something is done can be enforced against existing installations. It's what the United States Constitution calls an "ex post facto" law and it is constitutionally prohibited and it doesn't get any more bomb proof than that." I give it fifteen seconds and say "I'm sure you don't want the mother of a disabled adult child going to State Senator XXXXXXX who as you may already know sits on the public service commission. So when can I expect service connection?" Totally exasperated engineer answers "Monday." Me "Great is there anything else. Engineer "No Good day" click. He was as good as his word. Connection occurred the following Monday. Rapid repartee is just not me! I had been rehearsing various forms of that conversation for days.

Next I will get the 3 Intermodal Bulk Containers (IBCs) for liquids,
IBC Tote.jpg
that hold 320 gallons apiece, set up on a ledge cut into the rock on one side of their basement. I have a friend who did fire sprinkler pipe fitting for much of his career. He and I are going to build them a limited water supply sprinkler system using that 960 gallons as the supply. It might not put a fire completely out but I'm confident that it will hold it in check long enough for the first due engine to get there and pull the two of them out. The house is insured.
 
Interesting story ..

I would think 1 main breaker is sufficient to accommodate an immediate power shut down of the residence during an emergency.

I've had to Install several simple Fire type pull stations that control a horn to accommodate a special needs or toddler watching, type assistance residence.

Typically the red station pull switch had to have the glass rod intact while being enclosed within a clear easy accessible protective cover, normally located at 5ft, near a front door or approved egress path, the bell or horn was typically approved in hallways or stairwells.
 
I would think 1 main breaker is sufficient to accommodate an immediate power shut down of the residence during an emergency.
The main breaker is sufficient if it is mounted at an accessible location outside the building. The new code provision requires the emergency disconnect to be outdoors so that first responders can disconnect the power prior to entering the structure.

If your doing service a capacity increase; heavy up; on an indoor Service Disconnecting Means (SDM) that will now be a little more challenging. All of your branch circuit wiring is located at the indoor panel's location. I see 2 obvious approaches.

One is to obtain a Main Lug Only (MLO) panel in the size you need for the new service ampacity and a 3R enclosed main breaker. Install the enclosed breaker as the SDM. Install the required feeder conductors between the new exterior SDM and the MLO panel inside, Add the separate Equipment Grounding Conductor (EGC) termination busbars in the indoor panel. terminate all of the EGCs to the separate EGC Busbars. Remember to not install a Main Bonding Jumper (MBJ) in your MLO panel that would bond the neutral conductor to the panel's cabinet. All the rest is pretty much the same as any other heavy up.

My other approach would be to obtain a new main breaker panel. Right now those are markedly cheaper; at least here; than an MLO panel with the same number of breaker slots. Cut the meter tail at a convenient point between the meter enclosure and the indoor Main Breaker SDM panel inside the building. Install a 3R enclosed breaker for use as the emergency disconnect. [The NEC specifically allows the use of a 3R main breaker enclosure marked "Suitable For Use As Service Equipment" for use as the emergency disconnect WITHOUT making it the SDM. All we have to do is connect the 2 cut ends of the meter tail to the enclosed main breaker and "let it eat." That saves a lot of money and time.

[If I could find a 3Ø MLO panel with six slots I would install that as the emergency disconnecting means and the external manual generator transfer switch. I'd install a listed rocker style mechanical interlock between the 2 breakers and leave my generators with the neutral of the windings bonded to the frame. Then no matter were I was using the generators and what I was powering it with the generators would be properly configured.]

Tom Horne
 
FWIW, :), they are 330 gallons for the large ones (6 55 gallon drums) or 275 for the small ones (5 55 gallon drums).
Yes and thank you for offering the reminder. We have to leave some expansion room in each IBC. I think there is enough room on the ledge that we could fit 5 of them and I'm sure we could fit 4 but for right now we will start with the 3 that we have in hand. Do you happen to know how tall the smaller ones are? We may have enough room to stack them 2 high. I found one statement that they are 46 inches high. I make that 7'8". If that's right we will have to stay with the 330 gallon size. At 50" tall I know those will fit.

Strange thing is that the home already has a traditional rain gutter filled concrete cistern. As soon as I find someone who knows how to recoat fresh water concrete tanks who is willing to volunteer there time we can make the cistern water tight again. The well water in that area does not taste very good and it is very "hard." Cistern water is used for drinking, cooking, and washing your hair. Some folks also use it for washing clothes. Since the cistern is 8 feet long, 6 foot deep, and 2 foot wide that is 96 cubic feet. I make that ~718 gallons. We didn't consider using it for the fire sprinklers because the other uses would cause the volume to vary too much.

Tom Horne
 
Do you happen to know how tall the smaller ones are? We may have enough room to stack them 2 high. I found one statement that they are 46 inches high. I make that 7'8". If that's right we will have to stay with the 330 gallon size. At 50" tall I know those will fit.
If your 330's are 50", they are not what I recall; I do work for a local manufacturer of them. 275 are IIRC a cube, 46".

You must be talking without the base/cage. I don't believe you can stack them full without that support.
 
If your 330's are 50", they are not what I recall; I do work for a local manufacturer of them. 275 are IIRC a cube, 46".

You must be talking without the base/cage. I don't believe you can stack them full without that support.
It was just a number I found on one manufacturers website. Were would you suggest I look. I take it that they don't have standardized dimensions. The three we already have are the caged type. When I saw that they would fit on the ledge in the basement I didn't think to measure them. As I said I'm confident we can fit 3 of them. We may be able to fit 5. The height from the ledge to the underside of the floor joist above is about 5 feet.

Thomas Horne
 
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