• Welcome to the new and improved Building Code Forum. We appreciate you being here and hope that you are getting the information that you need concerning all codes of the building trades. This is a free forum to the public due to the generosity of the Sawhorses, Corporate Supporters and Supporters who have upgraded their accounts. If you would like to have improved access to the forum please upgrade to Sawhorse by first logging in then clicking here: Upgrades

new service panel w/o main

B

BSSTG

Gold Member
Joined
Nov 30, 2009
Messages
729
Location
Seadrift, Tx.
Greetings,

2014 NEC applies

So we have a new residential service panel rated 200 amp with no main. Electrician says he can do it since it has no more than 6 breakers installed. I say no. The six breakers are not listed as service equipment. Also, in reading ex 3 to 408.36 would lead me to believe that would not be the intent of the Code. However, reading ex 1 to 408.36 would lead me to believe you can if it's not a split bus.

What am I missing?

BSSTG
 
BSSTG said:
The six breakers are not listed as service equipment.
Click to expand...
If the panelboard is listed as service equipment the breakers listed on the label are suitable IF they have a high enough AIC rating.
 
When I run into a service with no main breaker I add up the amperage of all the breakers. Whatever that amounts to is the amperage that I ascribe to the "Main Breaker". So in this case there is a sub-panel that supplies most of the house. Let's say that the sub-panel is fed by a 100 amp breaker. Now we have five more breakers. Let's say that there is a 40 amp breaker for an A/C condenser. Then there are four 20 amp breakers for the rest of the house. Oops there's a 220 amp main on a 200 amp bus.

If the sub-panel is less than 100 amp (the minimum size service for a dwelling) or the house is large with a pool and Jacuzzi tub, electric stove, a laser for shooting down drones, etc., load calculations are in order.
 
Well I got my question answered. I called a state guy I know and he basically said that they see it as a loophole too and you have to allow folks to use the panelboard as service equipment without a main as long as they have no more than 6 breakers listed as service disconnects. 230.71 allow the six throws on a service and the exception 1 to 408.36 allows that (6 throws) in lieu of a panel board main breaker. My personal opinion is that it is kinda cheesy but it is what it is. He also suggested changing that by deleting the exception #1 to 408.36 by ordinance which is my thought too. I bet that the NEC will change on that at some time in the future. Of course someone needs to submit the change. The manufacturers that head up all of the code panels would probably go for the change as it will sell more main breakers!

BSSTG
 
ICE said:
When I run into a service with no main breaker I add up the amperage of all the breakers. Whatever that amounts to is the amperage that I ascribe to the "Main Breaker". So in this case there is a sub-panel that supplies most of the house. Let's say that the sub-panel is fed by a 100 amp breaker. Now we have five more breakers. Let's say that there is a 40 amp breaker for an A/C condenser. Then there are four 20 amp breakers for the rest of the house. Oops there's a 220 amp main on a 200 amp bus. If the sub-panel is less than 100 amp (the minimum size service for a dwelling) or the house is large with a pool and Jacuzzi tub, electric stove, a laser for shooting down drones, etc., load calculations are in order.
Click to expand...
ICE

If the calculated load of the service does not exceed the rating of the panelboard you are ok. The total amperage rating of all breakers added up can exceed the rating of the service panel, it just can't exceed the total calculated load for the service..... see 230.90 (a) ex#3 (2014 NEC)

BS
 
BSSTG said:
ICE If the calculated load of the service does not exceed the rating of the panelboard you are ok. The total amperage rating of all breakers added up can exceed the rating of the service panel, it just can't exceed the total calculated load for the service..... see 230.90 (a) ex#3 (2014 NEC)

BS
Click to expand...
I understand where you are coming from. The only time that this comes up is when they want to add solar. What happens is there is an old pushmatic panel with six breakers. The plan is to install a sub-panel and take some of the load to the sub-panel and introduce the solar contribution at the service or sub-panel. So they usually install a 50 amp two pole at the service to feed the sub-panel.

Because there is a solar contribution there must be a determination of the main breaker. There is no main breaker so what is the next best option? If there was one 100 amp main breaker we would of course say it is a 100 amps. If there are six breakers to flip for the same result as a 100 amp main, well then we add them up and that is your main. Another way to look at it is that if there is a 100 amp main breaker, the most that will get to the bus is 100 amps. If there is no main breaker the most that can get to the bus is whatever the six breakers happen to be. By the way, this was not my idea and comes from our electrical engineer.

I understand that this is counter-intuitive. But when adding solar there is a reason to fix an amperage to the panel. That has to do with the 120% allowance. I for one would never add solar to these antiquated panels and there is usually a reason to prevent it.
 
2013 CEC 230.71 Maximum Number of Disconnects.

(A) General. The service disconnecting means for each service permitted by 230.2, or for each set of service entrance conductors permitted by 230.40, Exception No.1, 3, 4, or 5, shall consist of not more than six switches or sets of circuit breakers, or a combination of not more than six switches and sets of circuit breakers, mounted in a single enclosure, in a group of separate enclosures, or in or on a switchboard. There shall be not more than six sets of disconnects per service grouped in anyone location.

For the purpose of this section, disconnecting means installed as part of listed equipment and used solely for the following shall not be considered a service disconnecting means:

(1) Power monitoring equipment

(2) Surge-protective device( s)

(3) Control circuit of the ground-fault protection system

(4) Power-operable service disconnecting means
 
I have an issue that come up today, I am slightly confused on the issue. Older home, moving the service entry point. 100 Amp meter socket, but no main disconnect. The breaker panel inside does have a main breaker. The panel is within 6ft of the front door. Poor family, trying to save money. Is this within code? Or is an exterior main disconnect still required?
 
Run the cable on the outside OK....inside other than a "reasonable straightish drop...NG.....Nearest the point of entrance is the verbiage and the problem is, once you allow those unfused conductors in the house, there is nothing that disallows someone to conceal them...And they and the transformer pop when they get hit
 
mark handler said:
2695-856e6e88f6dd3b313a6a72652f6fd511.jpg
Click to expand...

:eek::eek::eek::eek:
 
BSSTG said:
Well I got my question answered. I called a state guy I know and he basically said that they see it as a loophole too and you have to allow folks to use the panelboard as service equipment without a main as long as they have no more than 6 breakers listed as service disconnects. 230.71 allow the six throws on a service and the exception 1 to 408.36 allows that (6 throws) in lieu of a panel board main breaker. My personal opinion is that it is kinda cheesy but it is what it is. He also suggested changing that by deleting the exception #1 to 408.36 by ordinance which is my thought too. I bet that the NEC will change on that at some time in the future. Of course someone needs to submit the change. The manufacturers that head up all of the code panels would probably go for the change as it will sell more main breakers!

BSSTG
Click to expand...

A bit delayed on my response, but I found this very interesting, and I am somewhat on the fence. I would agree that it is probably not a common residential practice and that it could potentially cause future problems to individuals that are not trained to recognize this type of installation (homeowner wanting to add their own circuit in their home - permitted in my jurisdiction, and individual can certainly be untrained). However, thinking about this on a commercial scale, sectional switchgear used as service equipment also have the ability to exceed the six disconnect limit, but is listed, labeled, designed, approved and installed all the time with this ability. The difference is that altering such equipment is scrutinized by multiple individuals for code compliance prior to those alterations. Changing the NEC to protect untrained individuals could be a tricky endeavor. As a code official, I believe I would investigate these residential applications more closely, in that I would ask the installer to provide me with the product listing and labeling information as it relates to what they installed. Generally speaking, if equipment is suitable for the installation, it should be labeled accordingly. I saw one labeled "Suitable For Use as Service Equipment When Not More Than Six Service Disconnects Are Installed" and it had a configuration of six circuit breakers that filled all the spaces provided with it. If the installation didn't follow the configuration, it could be cause for concern (not installed per manufacturer/listing). I don't think you will find language like this with a 42 circuit MLO panel. I did see one, but it stated "only suitable for service equipment when a 125A max main breaker is back-fed in branch position and used with main breaker retainer clip cat # MBR1." In short, I just don't think you can take any MLO panel and turn it into a service "Suitable For Use as Service Equipment When Not More Than Six Service Disconnects Are Installed".
 
You must log in or register to reply here.
Top