• Welcome to The Building Code Forum

    Your premier resource for building code knowledge.

    This forum remains free to the public thanks to the generous support of our Sawhorse Members and Corporate Sponsors. Their contributions help keep this community thriving and accessible.

    Want enhanced access to expert discussions and exclusive features? Learn more about the benefits here.

    Ready to upgrade? Log in and upgrade now.

400A Meter Main Questions

C

CFD925

REGISTERED
Joined
Dec 27, 2023
Messages
6
Location
Commerce
Hello All,

I have a question concerning the 2020 NEC Changes in 230.70, 230.71, specifically 230.71(B): Prior to 2020 NEC, a 400A meter Main allowed 2 x 200A Main Breakers in the same cavity/enclosure. According to the 2020 NEC, a change was made which required each 200A Breaker be separated either using a 400A Meter Socket and a 200A disconnect on each side or vertically with a partition. I have a guy that is arguing his "Old Style" 400A Meter Main with the dead front attachment is code compliant. Sorry, I can't insert the pictures like I wanted.

When the dead front removed, there are two 200A breakers in the same cavity/enclosure. There is a dead front attachment (like a "T" bar) from Square D and it does make the two switches into one switch, I get that. However, it does not provide any safety from arc flash or electrocution if the dead front is removed. In my mind and research, safety was/is the point of the code change. Square D is also saying the dead front attachment meets code. I don't see it!

I have found only one thread on here so far with info on this topic. 2020 NEC Changes to 230.71 Service Equipment Disconnecting Means Maximum Number of Disconnects | The Building Code Forum I've inserted this link of a Mike Holt interview which gives support to my point/question.
I will continue to research. Our plan reviewer and I have the same opinion. He's a 40 yr Master Electrician.

I'd like to hear from all of you concerning this matter.

Thank you for reading and anticipated reply!

Have a great weekend!
 
I agree with your interpretation. This was a significant change in the electrical code, and one that can slip under the radar pretty easily. As is usual, experienced installers, even the very best, make the assumption that the way they have been doing is still "code compliant" because they are unaware of the change. Whenever I get these kinds of arguments, I ask them to pull out their code book and show me.

"Oh, what's that? You don't have a current code book? Or any code book? Okay, let me get mine."

That usually does the trick.
 
What's the make and model number of the meter main?

Is this a new install? For existing equipment, the 2023 NEC adds an exception to 230.71(B):

2023 NEC 230.71(B) said:
Exception to (2), (3), (4), (5), and (6): Existing service equipment, installed in compliance with previous editions of this Code that permitted multiple service disconnecting means in a single enclosure, section, or compartment, shall be permitted to contain a maximum of six service disconnecting means.
Click to expand...

Cheers, Wayne
 
This question came up on another forum:

2020 NEC Compliant 400A Common Disconnect Kit

Good morning, my AHJ has received a request if this "common disconnect accessory kit" would be accepted to meet the requirements of the 2020 NEC 230.71B. Would you consider this to be a 2. Panelboards with a main service disconnecting means in each panelboard enclosure You could operate each...
forums.mikeholt.com

Seems like the question is whether the kit turns two separate disconnecting means into one single disconnecting means. 230.90(A) includes the text "Single-pole circuit breakers, grouped in accordance with 230.71(B), shall be considered as one protective device." So the idea that handle ties can turn multiple devices into a single device is present in Article 230. [The reference to 230.71(B) appears to me to be left over from the 2017 NEC's version of 230.71(B).]

Cheers, Wayne
 
Wayne,

I see that side of the equation. Maybe this issue should have been addressed under NEC 230.70 Disconnects.

However, the kit is mounted to the face of the dead front. When removing the dead front, you still have two disconnecting means in the same cavity/enclosure which defeats the safety reasoning behind the 2020 code change (when this all started). The wording "separate enclosures" in 2020 and 2023 NEC 230.71(B)(1) makes me think of this 400A meter main by Siemans MK0402L1400SC or a 400A Meter socket with two separate 200A disconnects, one on each side. Both have two separate enclosures, 1 for each disconnecting means.

All in all, with the dead front removed from the Square D RC816D400SL, there still can be accidental arc flash and/or electrocution whether or not the kit is installed.

At the end of the day, I just want everyone safe and be able to go home!
 
CFD925 said:
However, the kit is mounted to the face of the dead front. When removing the dead front, you still have two disconnecting means in the same cavity/enclosure which defeats the safety reasoning behind the 2020 code change (when this all started).
Click to expand...
Well, that raises the question of what the safety reasoning is. If you have a single disconnecting means in a single enclosure, then obviously there's still a risk if you remove the dead front while that disconnecting means is "on". So I presume you are supposed to turn off the disconnecting means before you ever take off the dead front. And then if you do, and the line side lugs on the disconnecting means are guarded, that's about as safe as you can make it without getting the POCO to kill the line side conductors.

But for the case of multiple disconnecting means in one enclosure, there is the additional risk that the user will turn off only the disconnecting means they are working on, then remove the dead front, and thereby be exposed to the live load side lugs of the other disconnecting means and any wires connected to them. So avoiding that possibility is my understanding of the point of 2020 NEC 230.71(B).

However, in the case in the OP, the CDK400 ensures that if you shut off one of the two breakers before removing the dead front, you must shutoff both. So I'm not seeing any increase in risk with that over a single breaker in one enclosure. In both cases you could remove the dead front before turning off the disconnect, and in both cases you could turn on a breaker after the deadfront is removed. Obviously you shouldn't do either of those.

In other words, what sequence of steps/interactions would be safe for a single breaker as a service disconnect, but would not be safe for a RC816D400SL + CDK400?

Cheers, Wayne
 
Thanks again for providing additional insight Wayne! Well explained!! I'm getting it now.

My Dad always said I was hardheaded. Sometimes it shows more than others :)

Thanks again!!!
 
The 400 amp service panel with the pair of 200 amp breakers and a handle tie in order to meet the code is perhaps a suitable solution however, the common scenario that comes to mind is that of an ADU and a primary dwelling fed from the 400 amp service point. If there is a handle tie for the 200 amp breakers that serve the ADU and the primary dwelling.... well I suppose that you can see the conundrum this presents.
 
Can you demonstrate compliance with the following:

230.71 Maximum Number of Disconnects.
Each service shall have only one disconnecting means unless the requirements of230.71(B) are met.

(B) Two to Six Service Disconnecting Means. Two to six service disconnects shall be permitted for each service permitted by230.2 or for each set of service-entrance conductors permitted by 230.40, Exception No. 1, 3, 4, or 5.
The two to six service disconnecting means shall he permitted to consist of a combination of any of the following:

(1) Separate enclosures with a main service disconnectingmeans in each enclosure.

(2) Panelboards with a main service disconnecting means in each panel board enclosure.

(3) Switchboard(s) where there is only one service disconnect in each separate vertical section where there are barriers separating each vertical section.

(4) Service disconnects in switch gear or metering centers where each disconnect is located in a separate compartment.
 
ICE said:
Can you demonstrate compliance with the following:
Click to expand...
The logic would be that the CDK400 kit converts RC816D400SL from having two disconnects in a common enclosure to having only one disconnect. There is, after all, only one handle to push. So 230.71(B) "Two to Six Service Disconnecting Means" would not apply.

Cheers, Wayne
 
wwhitney said:
The logic would be that the CDK400 kit converts RC816D400SL from having two disconnects in a common enclosure to having only one disconnect. There is, after all, only one handle to push. So 230.71(B) "Two to Six Service Disconnecting Means" would not apply.

Cheers, Wayne
Click to expand...
Which of the four conditions is met by the CDK400 kit?

I see the logic and I stated earlier that the handle tie "is perhaps a suitable solution" however, logical and suitable are a common sense approach that is seldom found in the NEC. It seems to me that if the handle tie was acceptable to the NEC, there would be a fifth condition with 230.71(B).
 
Last edited:
The individual circuit breaker is the disconnecting means. The handle tie is a method to open two disconnecting means simultaneously. Multiple disconnecting means violates 230.71.
 
ICE said:
The individual circuit breaker is the disconnecting means. The handle tie is a method to open two disconnecting means simultaneously. Multiple disconnecting means violates 230.71.
Click to expand...
The definition of disconnecting means is "A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply." So a group of devices can be a disconnecting means.

CDK400 takes the two devices and turns them into one disconnecting means. There is only a single action required to disconnect power, you push one handle over. Not two separate actions like there was before CDK400 was installed.

Cheers, Wayne
 
230.71 recognized the multiple disconnecting means and provided four conditions as a way to accommodate the multiple disconnects. If the issue is made moot by the use of a handle tie, there would be an indication of that beyond logic. Your claim that the sentence which states that only one disconnecting means is allowed as proof that any number above one is possible by adding hardware is a stretch too far and unnecessary.
 
ICE said:
Your claim that the sentence which states that only one disconnecting means is allowed as proof that any number above one is possible by adding hardware is a stretch too far and unnecessary.
Click to expand...
I made no such claim. I said that the CDK400 kit makes it one disconnecting means.

If you have a 2 space enclosed breaker as the service disconnecting means, and it is populated by two single pole breakers with a handle tie, are you going to tell me that 230.71 prohibits that? How is that different from a fused disconnect with two fuses? In both cases manual operation requires just one action and both poles are disconnected, that's your only option. And automatic operation on one leg may not disconnect the other leg.

The CDK400 kit turns an install of two service disconnecting means that would be subject to 230.71(B) into an install with only one disconnecting means. In evaluating such an install for 230.71 compliance, we don't even have to read 230.71(B). The install satisfies the first sentence of 230.71.

Cheers, Wayne
 
wwhitney said:
The definition of disconnecting means is "A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply." So a group of devices can be a disconnecting means.

CDK400 takes the two devices and turns them into one disconnecting means. There is only a single action required to disconnect power, you push one handle over. Not two separate actions like there was before CDK400 was installed.

Cheers, Wayne
Click to expand...
We know that from the factory, the 400A RC816D400SL is not compliant with the 2020 NEC. The real debate here appears to be whether or not the kit sold that turns both disconnects into one meets the intent of the changes in the 2020. I have some questions that I would want answered if I were to put this on an approved list for my jurisdictions.

  1. Is the kit provided by the manufacturer?
  2. Is the kit approved by the manufacturer?
  3. Is the kit listed or labeled by any of the NRTLs?
 
wwhitney said:
Yes, here are the installation instructions:

Common Disconnecting Mechanism Kit for CSED 400 A | Schneider Electric

This bulletin provides instructions for installing the Common Disconnecting Mechanism Kit onto CSED 400 A meter center using QBL/QDL/QGL/QJL type...
www.se.com www.se.com

Not sure about the listing/labeling question, nor where to find that info.

Cheers, Wayne
Click to expand...
The fact that it is provided for by the manufacturer with compatible catalog numbers is reassuring.

However, the fact that they are not showing that it is listed or labeled takes away from that warm and fuzzy feeling I like to have. It looks like a knee-jerk reaction to a code change they did not anticipate well, and are scrambling for a fix without following the normal steps. This, in my litigation experience, tells me that it is possible they don't market this or provide listing and labeling as an excuse for a 'buyer beware' or 'I never said' defense.
 
ICE said:
It would be helpful to have an understanding of the reason for the code change.
Click to expand...
Per the 2020 NEC First Draft report, this change was initially adopted as FR-8463-NFPA 70-2018 by CMP 10. I did not check the Second Draft Report. There were 3 PIs proposing a change like this (including some proposing a requirement for a single disconnect) with various safety arguments. The CMP's statement in adopting the change was:

FR-8463-NFPA 70-2018 Committe Statement said:
This revision recognizes challenges created with more than one service disconnecting means in the same panelboard or other enclosure. This proposed revision continues to retain the six service disconnect rule for services. However, to address these challenges, the permission for up to six service disconnects is modified to require installation in separate enclosures.

This revision provides the ability for an installer/maintainer to operate a single disconnect that deenergizes conductors and circuit parts in the enclosure except for the line side of the disconnecting means. This reduces the likelihood of an incident with energized conductors or circuit parts in the service equipment, enhancing safety.

This action must be coordinated with the deletion of 408.36 Exception No.1. This exception is based upon the existing permissive rules in 230.71. CMP-10 requests that the NEC Correlating Committee review these actions and provide Correlating Committee notes if necessary.
Click to expand...

Cheers, Wayne
 
You must log in or register to reply here.
Back
Top