- Location
- Simi Valley, CA
Yes it does. In some of the older panels you had MLO so if you had six disconnects and added an A/C later, you don't have to replace the panel.
Main breaker
- Thread starter GG
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Yes it does. In some of the older panels you had MLO so if you had six disconnects and added an A/C later, you don't have to replace the panel.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
We did not get inspections or permits in our county until after 2005, The poco would hook up anything that didn't blow up when they put the meter in. A whole lot of mobile homes with three wire feeds, with not even a jumper between the ground and neutral buss inside. Got plenty of calls from people getting shocked off the door knobs.
GG
Senior Member
- Location
- Ft.Worth, T.X.
Sorry, I missed that question. No, they are not split bus panels. Was federal pacific the only company to make split bus panels as thats the only brand I have run accross?
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
GG
Senior Member
- Location
- Ft.Worth, T.X.
Were the split bus panels made to have a max of 6 breakers to satisfy 230.70? I thought it had to do with manufacturing costs being lower to make a split bus panel over a main breaker panel. Thats what I was told, dont know if its true.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
The ones I ran across had four mains if I remember correctly, Usually one for the stove, one for the water heater, one for the dryer, and the last one feed the lower bus with 6-10 more breakers on it for lighting and receptacles.
OK, I can see the exception as not requiring individual protection for the existing panelboard. I don't see that the exception allows one to exceed the six disconnect rule as provided in 230.71.
By the way, what code cycle are we talking about? Must be 2005?
kbsparky
Senior Member
- Location
- Delmarva, USA
Concerning the use of split-bus panels, the NEC effectively did away with those with the 1981 edition of the Code. The word "existing" was inserted into the text of exception #2 of section 384-16(a), requiring individual protection of lighting and appliance panelboards used as service equipment in dwellings.
- Location
- Simi Valley, CA
Yes 2005.
The exception that allows you to not have a main is the same one that allows more than six disconnects. You start at the six disconnect rule and you end up in the main not required. Remember you only need a main if you have more than six disconnects, so this exception is saying that you don't in an existing residential service panel.
Also while I know it's not code, look at the comentary in the handbook. And one more time for those that are hard of reading, I KNOW IT'S NOT CODE.
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jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Yes 2005.
The exception that allows you to not have a main is the same one that allows more than six disconnects. You start at the six disconnect rule and you end up in the main not required. Remember you only need a main if you have more than six disconnects, so this exception is saying that you don't in an existing residential service panel.
Also while I know it's not code, look at the comentary in the handbook. And one more time for those that are hard of reading, I KNOW IT'S NOT CODE.
Okay, I will at commentary in handbook at lunch time. I only carry regular NEC at work. I will admit that you are probably right, I am just being stubborn.
Yes 2005.
The exception that allows you to not have a main is the same one that allows more than six disconnects. You start at the six disconnect rule and you end up in the main not required. Remember you only need a main if you have more than six disconnects, so this exception is saying that you don't in an existing residential service panel.
Also while I know it's not code, look at the comentary in the handbook. And one more time for those that are hard of reading, I KNOW IT'S NOT CODE.
I don't have the 05 handbook. I am curious as to what it says.
The charging statement in 480.36 requires individual protection. The exception waves this "individually protected" requirement. I still don't see the language allowing more than six service disonnects.
- Location
- Simi Valley, CA
Here's the commentary. The phrase "for existing installations" in Exception No.2 refers to the existing panelboard. It is not intended that a split-bus panelboard used in an individual residential occupancy be replaced if a circuit is added to the existing panelboard.
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
OP said panel is not split bus.
- Location
- Simi Valley, CA
And I'm not sure why the commentary says split bus. 408.36 does not mention split bus nor does 230.71.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
It may not say it, but that is why it is there. Split bus panels were common in the 70's. I've had two houses with Cutler Hammer panels done this way. The top 12 slots are intended for double pole breakers and are your disconnects. One of those feeds the lower section of bus stabs usually via a 60A breaker. These has factory #4 pigtails on the lower bus that came up to one of those 6 double pole breaker positions.
The 6 disconnect rules has been in the code for a long time. The main breaker required for Lighting and Appliance panels was added in the 80's, but they had to cover all those existing split bus panels so the exception was added. There are two types of service panels -- those with a main breaker, and those with 2 to 6 breakers which shutdown all the bus stabs. MLO panels are not Suitable for use as Service Equipment unless they have 12 slots or less and you don't exceed the 6 breaker limit.
The existing panel exception usually doesn't allow something that was never compliant to be excepted (or accepted).
The 6 disconnect rules has been in the code for a long time. The main breaker required for Lighting and Appliance panels was added in the 80's, but they had to cover all those existing split bus panels so the exception was added. There are two types of service panels -- those with a main breaker, and those with 2 to 6 breakers which shutdown all the bus stabs. MLO panels are not Suitable for use as Service Equipment unless they have 12 slots or less and you don't exceed the 6 breaker limit.
The existing panel exception usually doesn't allow something that was never compliant to be excepted (or accepted).
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Maybe because a split bus panel was legal at the tome. A split bus obeyed the 6 switch rule. But a MLO panel full of breakers coming straight off a meter can was wrong to start.
Maybe this got passed the way Mcclary said. Put in 6 breakers, pass inspection, and then go back and fill the panel up.
- Location
- Simi Valley, CA
I won't say that that's not possible, but I have whole tracts of houses here with Zinsco panels and no mains in them, built in the 60's and 70's.
Could be an interesting question for the CMP on what the true intent was.
Like I mentioned before the exception simply says "lighting and appliance branch-circuit panelboards". Makes no mention of split-bus. The code section says that it can't be feed by more than two main circuit breakers. which to me means one or two.
You can imagin as an inspector how well it would go over when I told the home owner that just put in that $6000 A/C system that they were going to have to spend another $3000 for a service change even though the panel would handle the additional load.
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Isn't this where a reputable and knowledgeable EC steps up to the plate and says "Mam, if I install this I'll have to change the service because I cannot alter this and create a code violation. 230.71 is not new!
jumper
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- 3 Hr 2 Min from Winged Horses
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