View Full Version : 200 Amp Service Panel with 60 Amp Main Breakers
hlmccarter
Mar 6, 2007, 07:10 PM
I was told when we purchased our house that it had 200 Amp service which it appears to be; however, the top of each bus bars only has 60 Amp breakers for the Main shut offs. Is this normal? Each bus bar is connected to a hot wire (one red and one black) and then the two 60 amp breakers are connected with fat wires to each other. Anyway I don't ever do more than minor electrical work, but this seemed a bit odd to me and wasn't sure if it was ever done and more importantly and explanation on why please!
Any input would be great.
nmwirez
Mar 6, 2007, 11:23 PM
I was told when we purchased our house that it had 200 Amp service which it appears to be; however, the top of each bus bars only has 60 Amp breakers for the Main shut offs. Is this normal? Each bus bar is connected to a hot wire (one red and one black) and then the two 60 amp breakers are connected with fat wires to each other. Anyway I don't ever do more than minor electrical work, but this seemed a bit odd to me and wasn't sure if it was ever done and more importantly and explaination on why please!
Any input would be great.
Your description is not clear to me. Locate where the meter is and see if it has a disconnect breaker. Then follow the meter conduit or cable interconnection to the panelboard.
The panelboard may be a MLO (main lug only) hookup on top to the bus bars lugs along with one neutral cable in the panel. A 200 amp service connection requires a 2/0 awg copper or 4/0 awg Aluminum from the meter to a disconnect breaker. Does any of this match what you have? Nm.
tkrussell
Mar 7, 2007, 03:36 AM
Can you provide a picture of the opened panel with the wires and these breakers you mention?
hlmccarter
Mar 7, 2007, 05:14 AM
Can you provide a picture of the opened panel with the wires and these breakers you mention?
Hopefully these pictures help. The first is the overall panel and the 2nd is a zoom in on the two hot wires and the 60 amp breakers in question. Thx for your help everyone!
http://www.fileden.com/files/2006/9/12/215564/DSCN1444.JPG
http://www.fileden.com/files/2006/9/12/215564/DSCN1443.JPG
tkrussell
Mar 7, 2007, 10:17 AM
OK I give up, what are those two 60 amp breakers for? They certainly are not the main for this panel, this is a MLO, Main Lug Only panel, as suspected by nmwirez. And as he mentions there should be a Main Breaker at the meter, or somewhere upstream of this panel.
The two heavy black and red cables coming in from the large cable at the top center should be the incoming hot feeds to this panel.
Actually appears that the wires leave the breaker on the left, go up over and under all the breakers in the panel, exited the bottom, and connect to the breaker on the right.
After doing a triple take, I am sure this is what I see, and I have absolutely no idea why.
Every day I thing I have seen it all, then comes along another picture of something wacky.
I cannot come up with any purpose for this arrangement. Can you unplug all the other breakers to see if what I think I see is correct? These two 60 amp breakers and connected cables should not be there and should be removed, unless someone can give me a reasonable answer why they are there and should remain.
hlmccarter
Mar 7, 2007, 11:15 AM
OK I give up, what are those two 60 amp breakers for? They certainly are not the main for this panel, this is a MLO, Main Lug Only panel, as suspected by nmwirez. And as he mentions there should be a Main Breaker at the meter, or somewhere upstream of this panel.
The two heavy black and red cables coming in from the large cable at the top center should be the incoming hot feeds to this panel.
Actually appears that the wires leave the breaker on the left, go up over and under all the breakers in the panel, exited the bottom, and connect to the breaker on the right.
After doing a triple take, I am sure this is what I see, and I have absolutely no idea why.
Every day I thing I have seen it all, then comes along another picture of something wacky.
I cannot come up with any purpose for this arrangement. Can you unplug all the other breakers to see if what I think I see is correct? These two 60 amp breakers and connected cables should not be there and should be removed, unless someone can give me a reasonable answer why they are there and should remain.
You are right those breakers are connected and I would have absolutely no idea as well. I'll look for a main cutoff but I really don't think there is one outside. If there isn't common sense would seem that I should indeed have a professional replace that panel. What started this all was I just wanted to add a few more circuits and that panel is tapped out of room so I was just going to use some of those double breakers to get the room needed to add them.
From the wiring do you think you can confirm if it's a 200 amp service or possibly less? Is there a way to test the amperage with a multimeter or something?
tkrussell
Mar 7, 2007, 11:22 AM
The two heavy feeders I see do appear to be #4/0 SEU cable which is 200 amp rated.
I did not get into before, but maybe should now, that this is a three wire feed, and if there is a Main Breaker, and hopefully there is, upstream, then the cable should be a four wire, with an insulated neutral, and a separate bare or insulated ground.
EDITED TYPO 2:16PM Changed 20 to 200 amp
hlmccarter
Mar 7, 2007, 11:48 AM
There is a ground wiring in the system, but it appears to be added after the fact. The wiring from the source does indeed have two hot wires and then what appears to be aluminum neutral wire that is broken down into several strands.
If there is no main upstream would you recommend replacing the panel? And also from what we have talked about it seems like I could pull those 60 Amp breakers since all they appear to do is bridge the two hot buses, which would give me the room in the panel I need to add circuits. Bad idea?
tkrussell
Mar 7, 2007, 12:36 PM
FYI I went back and edited my typo from 20 amp to 200 amp in my previous answer.
No, good idea to pull out those breakers, not sure what someone was trying to do, but does not matter, pulling them out should have no effect on the operation of the panel, and will free up 4 pole spaces for you.
I see the copper ground, but I assume that goes to a grounding electrode, such as a ground rod.
If there is a Main elsewhere, then the bare neutral cannot remain. If there is no Main elsewhere, one needs to be installed, which can be remote or in the panel.
Changing the panel may be a good idea, due to age and the rust I see. That type of cable, SEU , is popular for allowing water into panels.Once a breaker gets wet it needs to be replaced per UL and the manufacturer's requirements
hlmccarter
Mar 7, 2007, 12:43 PM
Thx for the info. I do have one more question. What do you mean by the bare neutral cannot remain if there is a main upstream? Are you saying the neutral wire should be replaced? If so isn't that something the electric company would do rather than an electrician?
tkrussell
Mar 7, 2007, 01:02 PM
Once a service entrance feeder leaves a Main Service Disconnecting Means, the Neutral is to be insulated and isolated from the equipment ground, which can be insulated or bare. At the panel the Neutral is isolated from any grounded metal,scuh as the panel back box, and equipment grounds are separated.
The utility usually only provides the aerail cable from the pole to the houise, and the customer owns and maintains the wiring and equipment from that point of conncetion,which is the cable on the house, the meter, feeder from meter to panel, etc. So an electrician hired by the customer handles all of this wiring and equipment.
hlmccarter
Mar 7, 2007, 03:43 PM
I am further complexed. I just tripped those 60 amp breakers and they did cut off power to their respective buses. This just floors me. The next step is to pull out the breakers and see what the bus looks like. How could they kill power to the buses if they are just wired together and the bus is hot?
tkrussell
Mar 7, 2007, 04:06 PM
I bet the bus is damaged or broken, and this was a quick fix. Please pull out all the other breakers so we can see what is going on inside. Do you have a voltage tester to see where the power is coming from?
I had a feeling something weird was going on.
nmwirez
Mar 7, 2007, 04:24 PM
FYI I went back and edited my typo from 20 amp to 200 amp in my previous answer.
No, good idea to pull out those breakers, not sure what someone was trying to do, but does not matter, pulling them out should have no effect on the operation of the panel, and will free up 4 pole spaces for you. tk, this may be a split bus, I could not tell from the photos I down loaded. I didn't get to see the bottom half of the pan. This was real common in the late 50's, early 60's and seeing the old 2/0 SEU at the top is a pretty good indicator of that era.
I see the copper ground, but I assume that goes to a grounding electrode, such as a ground rod.
If there is a Main elsewhere, then the bare neutral cannot remain. If there is no Main elsewhere, one needs to be installed, which can be remote or in the panel.
Changing the panel may be a good idea, due to age and the rust I see. That type of cable, SEU , is popular for allowing water into panels.Once a breaker gets wet it needs to be replaced per UL and the manufacturer's requirements
Thanks for that info on the change out. I can not believe this panel is not a split bus. It is completely out of character with the way the grounding is applied here. Anyway, the real deal about being a 200Amp is not true. Most real estate home inspectors have little experience in what they see inside a panel let alone open one up.:D
Nm
nmwirez
Mar 7, 2007, 04:33 PM
Whoops! I didn't see you guys posting while I was putting in my comments on the pictures. It is a split buss per the data I just read. Nm
hlmccarter
Mar 7, 2007, 04:45 PM
Ok so nmwirez says it's a split bus. Not exactly sure what that means? Why do the two 60 amp breakers in parallel kill the power to the breakers below them? Here are some pics behind of it opened up a bit...
http://www.fileden.com/files/2006/9/12/215564/DSCN1445.JPG
http://www.fileden.com/files/2006/9/12/215564/DSCN1446.JPG
The meter outside is fairly old as well and I got some quotes to replace the whole lot for 1800ish... might be worth it just to have that done and add some safety features to the place.
labman
Mar 7, 2007, 05:13 PM
Still can't see what I was expecting, a cut in the buss between the 60 amp breakers and the rest.
nmwirez
Mar 7, 2007, 05:25 PM
Maybe there is too much traffic on this post. My reply explaining what a split buss is and what the poster needs to do took a little time to write up and it just got bumped offline. Do not think that panel is broken and let me do a post about dog grooming later on. Nm
nmwirez
Mar 7, 2007, 06:03 PM
Whoops! I didn't see you guys posting while I was putting in my comments on the pictures. It is a split buss per the data I just read. nm
Sorry, My explanation was knocked offline just as I keyed in at the same time Labman replied. Unfortunately my reply carried the two pictures that didn't allow the answer to go through. Who knows.
There are two types of split busses which I do not have time to describe.
If you are going to add more capacity to the existing service I will recommend a more economical approach that may save some time and costs. Nm
nmwirez
Mar 7, 2007, 06:18 PM
Hlm
The easiest upgrade is to do a back to back with a panelboard with a 200a main disconnect. You will need a 200amp safety socket meter box with a drop service mast up through the roof unless a lateral is affordable.
In either case, replace the split panel with a new 20/30 or 20/40 200amp main (SQ D recommended) or match existing brand to save breakers.
A short nipple with insulator bushings through the wall will hook up everything easily. This is one of the most common methods for service entrance configurations and the most quick to install. May ask the bidders for this to reduce costs. All other grounding and bonding requirements remain intact as the split buss panel exists now. 2 ground rods though.
I hope this clears the smoke, nm
tkrussell
Mar 7, 2007, 06:50 PM
Really need to see the entire interior of the panel without any breakers in it to figure out what it being done here, and need to know where the power is coming form, should be the two large wires at the top, and these breakers should not have any effect, and those jumper wires certainly do not belong there.
At least they look like they jumper from one breaker on the right directly to the one on the left.
nmwirez
Mar 7, 2007, 07:47 PM
[QUOTE=hlmccarter]Ok so nmwirez says it's a split bus. Not exactly sure what that means? Why do the two 60 amp breakers in parallel kill the power to the breakers below them? Here are some pics behind of it opened up a bit...
Here is the reason,
A split buss panel is designed such that the upper buss half is used for a main disconnect for general circuits below and it carries the larger load on the top half of the split buss.
This type of panel is no longer NEC compliant or available.
nmwirez
Mar 8, 2007, 10:04 AM
[QUOTE=hlmccarter]Ok so nmwirez says it's a split bus. Not exactly sure what that means? Why do the two 60 amp breakers in parrallel kill the power to the breakers below them? Here are some pics behind of it opened up a bit...
Here is the reason,
A split buss panel is designed such that the upper buss half is used for a main disconnect for general circuits below and it carries the larger load on the top half of the split buss.
This type of panel is no longer NEC compliant or available.
I need to jump in here one more time. This is to clarify the back-to-back meter box through-wall conversion to a 200 Amp main disconnect panelboard. This requires a meter relocation from the work platform (grade) clearance to the meter. Check with the POCO before making any panel changeout decisions. They hold the magic key, not the building department. Usually a meter height from grade will be about 5 or 6 ft. On a down slope the POCO will allow 7 feet.(rarely) nm
tkrussell
Mar 9, 2007, 03:54 AM
So what is the verdict on your panel? Did you find where the power is fed into the panel? Did you look behind the breakers? We really would like to know what those two 60 amp breakers have to do with shutting off the power, when they should have no effect. The power is suppose to be coming in the on the two large wires connected to the lugs of the panel at the top, and feeds the two bus bars that are in behind all the branch breakers, including the two 60 amp breakers at the top. The wire terminals should only be hot when each breaker is on, as each breaker connects to power once they are plugged onto the internal bus bar.
The suspense is intense!
hlmccarter
Mar 9, 2007, 05:13 AM
After I pulled everything apart I found a split buss panel as nm proposed (although it didn't look like any I could find on the internet). Those 60 amp breakers each supplied power to the lower part of their respective sides (those wires actually completed the break in the buss circuit that was much lower than I expected). When you trip those 60's the lower buss loses power.
My only question now is whether I can up the amperage of those two breakers to provide more than 60 amps off each of the lower busses. My guess is I shouldn't do it and I'm getting quotes to have the entire panel replaced but since everything appears to be in working order and I understand the safety implications I might hold off a bit until I save enough to replace it.
Thx for everyone's help.
tkrussell
Mar 9, 2007, 06:03 AM
Don't modify the panel any more than it is, and get the panel replaced as soon as you can.
Not a serious safety issue, as you know the bottom section of the opanel is only rated for 60 amps. Split panels are not norammly fed in this manner, does it appear to be factory made or "field modification"?
labman
Mar 9, 2007, 06:22 AM
Thank you for the update.
I didn't understand any of the breakers had power with the top ones off. With the split lower, the ones above it still would have power. If the 60's aren't tripping, you shouldn't get any more power by replacing them. If you did replace them, you might have to replace the wires with larger ones.
Unless you find and throw a disconnect to the feed, outside the box, I would put all the breakers back in and leave it that way. It would be safer putting the breakers back in if you found a disconnect. One slip, and touch the energized buss, and you are fried. A breaker somewhere protecting the incoming wires is required.
I am a bold DIY and likely go beyond where I should. I would button that panel up and leave it, until I could afford a professional.
That may be sooner than you think. Nobody can count on getting away with foisting off a Mickey Mouse set up by an unlicensed installer in violation of code. You were sold a house with a 200 service that must have met code at the time it was installed. Have a professional come and inspect it, and give you a estimate on what is needed to to make it the code compliant 200 amp service you paid for. That should be free. So should at least the initial discussion of the problem with the lawyer that handled your closing. If you didn't have a lawyer, talk to the Realtor. They represent the seller, but an ethical one will realize you have the law on your side. Your lender should back you and perhaps direct you to a good lawyer.