MLO as service equipment?

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NHsparky62

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Location
Dover, NH, USA
Can you use a MLO as a main service panel, with a service disconnect further down on the supply side? If yes, would I need to back feed it with a 100A breaker, and is that allowed by code? I've been searching through my code book all night and it seems to dance all around it, but I can't seem to find a clear answer. As for using it as a main service panel, it seems to me by what I've read that it's fine, with a service disconnect ahead of it. As far as back feeding, I've heard people on both sides, but the way I understand 408.36 (D) is that it's not an issue as long as you fasten the breaker down. I'm assuming it's okay to do the back feed method for that reason, but I still don't know if there is any reason I couldn't do that with service equipment. I would appreciate some input on this, and preferably the code articles to reference as well. Thanks!
 

Dennis Alwon

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Location
Chapel Hill, NC
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Retired Electrical Contractor
It sounds like the main lug panel is your first disconnecting means. If you have 6 breakers or less then that could be your service disconnecting means however you cannot have the service disconnect after this mlo panel. Also the mlo panel must be rated suitable as service equipment
 

NHsparky62

Member
Location
Dover, NH, USA
It sounds like the main lug panel is your first disconnecting means. If you have 6 breakers or less then that could be your service disconnecting means however you cannot have the service disconnect after this mlo panel. Also the mlo panel must be rated suitable as service equipment

The disconnect is on the SUPPLY side of the MLO panel. It is the first thing the service entry wires hit. And this is another thing... the 6 breaker rule, I've seen lots of people use the phrasing of "breaker" as a loop hole, calling a cheater breaker "one breaker". So they interpret it as six SPACES, not six CIRCUITS. I've also seen a fair amount of inspectors look at it the same way. And, as I mentioned before, it seems like back feeding a MLO panel is acceptable if you use the fastening bracket, per 408.36 (D).
 

augie47

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Location
Tennessee
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State Electrical Inspector (Retired)
Definitions mean a lot. If your disconnect ahead of the panel meets the definition of "service equipment" then this panel is not "a main service panel". It is simply "a panel" or a "sub-panel" (not NEC defined) and all the rules associated with a service panel such as number of disconnecting means, etc. don't apply.
Unless you are using a tap rule, you can feed the panel thru the lugs. IF you do elect to back feed a breaker, then it must be secured per 408.36(D).

(The rules change under "one building fed from another")

As far as your "6 breaker rule" 230.71 limits the number of switches and/or circuit breakers to six. I'm not familiar with your term "cheater breaker" but any or all of the six breakers can be two-pole or three pole breakers.
Some folks use the "six throws of the hand" rule.
 

NHsparky62

Member
Location
Dover, NH, USA
Definitions mean a lot. If your disconnect ahead of the panel meets the definition of "service equipment" then this panel is not "a main service panel". It is simply "a panel" or a "sub-panel" (not NEC defined) and all the rules associated with a service panel such as number of disconnecting means, etc. don't apply.
Unless you are using a tap rule, you can feed the panel thru the lugs. IF you do elect to back feed a breaker, then it must be secured per 408.36(D).

(The rules change under "one building fed from another")

As far as your "6 breaker rule" 230.71 limits the number of switches and/or circuit breakers to six. I'm not familiar with your term "cheater breaker" but any or all of the six breakers can be two-pole or three pole breakers.
Some folks use the "six throws of the hand" rule.

A "cheater breaker" is a trade name for a tandem breaker, or two single pole breakers in the space of one "normal" single pole size. It seems to me like most people try to twist the words so they can make it 6 spaces rather than 6 circuits, but hey, if it works and is safe, and the inspector is happy... all the power to ya.
I did buy a "main breaker panel" from HD, and the only difference from the MLO was that there were no main lugs. The "main" was back feeding it with a tie down strap, if you will.
I think I'm going to keep looking to find a true main breaker panel. Perhaps I should stop looking in places like Home Cheapo ;)
 

augie47

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Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Yep. That was a "brain cloud" on the 'cheater'. I have heard the term but it's not common here.
I would count a cheater breaker as two breakers, but as you say, if the inspector is happy........
 

david

Senior Member
Location
Pennsylvania
A "cheater breaker" is a trade name for a tandem breaker, or two single pole breakers in the space of one "normal" single pole size. It seems to me like most people try to twist the words so they can make it 6 spaces rather than 6 circuits, but hey, if it works and is safe, and the inspector is happy... all the power to ya.
I did buy a "main breaker panel" from HD, and the only difference from the MLO was that there were no main lugs. The "main" was back feeding it with a tie down strap, if you will.
I think I'm going to keep looking to find a true main breaker panel. Perhaps I should stop looking in places like Home Cheapo ;)

I have a problem these days making self determinations to what is safe. I find things that were insignificant in my reading or understanding of certain rules change overtime. My opinion of things that I thought where not so important changed.

I still at times find myself saying that?s not exactly what the code called for I?ll let it go this time and lets make sure next time>>>>>

As was said in the past the amount of disconnects was limited by a code panel many years ago if the limit to six disconnects is safe or not (arbitrary) I?ll leave that up to the book.

I do know however the rule is a disconnect rule, and not concerned with how many breakers and not concerned with how many circuits. It is a disconnect rule how many actions are provided for to disconnect the building / structure from the electric supply.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
The disconnect is on the SUPPLY side of the MLO panel. It is the first thing the service entry wires hit. And this is another thing... the 6 breaker rule, I've seen lots of people use the phrasing of "breaker" as a loop hole, calling a cheater breaker "one breaker". So they interpret it as six SPACES, not six CIRCUITS. I've also seen a fair amount of inspectors look at it the same way. And, as I mentioned before, it seems like back feeding a MLO panel is acceptable if you use the fastening bracket, per 408.36 (D).
Most panels that will accept "cheater" breakers, are listed for use as service equipment only where a single main breaker has been installed.
 

kwired

Electron manager
Location
NE Nebraska
A "cheater breaker" is a trade name for a tandem breaker, or two single pole breakers in the space of one "normal" single pole size. It seems to me like most people try to twist the words so they can make it 6 spaces rather than 6 circuits, but hey, if it works and is safe, and the inspector is happy... all the power to ya.
I did buy a "main breaker panel" from HD, and the only difference from the MLO was that there were no main lugs. The "main" was back feeding it with a tie down strap, if you will.
I think I'm going to keep looking to find a true main breaker panel. Perhaps I should stop looking in places like Home Cheapo ;)
What do you have for your first disconnecting means where service conductors end? If it is a disconnect with associated overcurrent protection - that is your service disconnecting means (must be listed as suitable for service equipment or you have other issues with it anyway). Beyond that you only need to protect any panelboards you supply at or below their rating, if the overcurrent device in the service disconnect is 100 amps you can feed how ever many 100 amp rated main lug panels you wish from an overcurrent protection perspective, load calculations may be a different story.

Six disconnect rule - means six movements of the hand must open all of the service disconnecting means. 6 three pole breakers only requires six movements of the hand even though you are opening 18 "poles" three "tandem breakers (if even suitable for use as service disconnecting means) has six handles and requires six movements of the hand to open all of them (doesn't consider the fact you probably have large enough fingers to hit all of them at one time - they are interested in the fact there is six separate handles)

Most panels that will accept "cheater" breakers, are listed for use as service equipment only where a single main breaker has been installed.
I think most "loadcenters" require a single main where used as service equipment, not by code but by their listing instructions.
 
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