Replaceing main breaker panel

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  #1  
Old 04-04-11, 07:15 PM
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Replaceing main breaker panel

I have a Zinsco 100Amp panel with a burnt buss bar that I need to replace. There is also a sub panel I want to eliminate. I will do this with a permit. But have some questions.

I want to use a 100 amp replacement panel for economy. I currently have

2 40A breakers AC and range

3 30A breakers

9 20A breakers

I need to add a 30A and 2 20A breakers, will this be too much for a 100A panel or what is the max amps on a 100A panel?

I've included a picture and have some questions on that. There is a wooden box from ceiling to panel in which the wires run, is a wooded box OK for this? If OK can I replace cover on box before calling for inspection?

There are 8 wires entering box through 1 1 1/2" clamp connector, Sure does not look right! How many wires can be in a clamp connector?

Thanks in advance JIm
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Old 04-04-11, 07:21 PM
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.......................100 amps max .................
 
  #3  
Old 04-04-11, 07:56 PM
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Best to do a load calculation but from what you say my guess would be it is best to go to 200 amps. http://www.bestinspectors.net/members/RES Service.xls

The wood chase for the cables is OK but bundling like that isn't. You need individual cable clamps. Usually no more then two cables per clamp depending on manufacturers recommendations.

The receptacle at the bottom of the left box should have been done with a nipple. The connectors for the FMC appear to be EMT connectors.
 
  #4  
Old 04-04-11, 07:59 PM
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Without knowing what all of the breakers go to and the calculated load, it's difficult to say. I can say, however, you are probably on the edge of what a 100 amp panel will handle. IF I were to go with a 100 amp panel, it would have no fewer than 30 circuits.
 
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Old 04-04-11, 08:01 PM
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Guess I asked the question wrong. OK so a 100A panel draws a 100A max! But the panel is not limited to 5 20A breakers. Is there a limit to the potential amp draw of the breakers in a 100A panel?

I am not concerned about the 100A service, I have lived with it for 2 years with no issues. We have a small house with 2 conservative adults. I do not want to have the inspector to fail it because of something in the NEC.
JIm
 
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Old 04-04-11, 08:02 PM
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As buzz said the max amps of a 100 amp panel is 100 amps of current. You do not just add up the numbers on the breakers. It is the total load that can be on the panel meaning you could have a Range, A/C, Dryer, tv, and computer running and still not exceed 100 amps. What you need to do is do a load calculation (Search Google for load calculation) to find out what your homes load is. This will determine your service size you need.

When you change out a panel you should leave as much as you can so the inspector can see what you did, as long as it is safe to do so.

All the cables going through the one connector is a no-no. Connecters are rated for a certain number and size of cables. I doubt that one is rated for 8 cables. You should use the proper 1/2 K.O. for your cables.
 
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Old 04-04-11, 08:09 PM
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Thanks for the quick responses!!!

What about the wooden box that the cables run in? It is a 2X3 on each side covered by 1/2 in plywood, the cover is off in the picture.
 
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Old 04-04-11, 08:20 PM
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I would just leave it off for inspection as long as it is safe to do so.
 
  #9  
Old 04-04-11, 08:23 PM
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So a wooden box is OK for protecting wires? JIm
 
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Old 04-04-11, 09:33 PM
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If you insist on keeping a 100 amp service I would suggest a GE TM3210CCU, 32 circuits, plenty of room. Normally all you are going to find is 20 circuit 100 amp panels but we need something a bit bigger. Sell those old Zinsco's on ebay.
 
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Old 04-05-11, 05:26 AM
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Please tell me that's not a doorbell transformer at the bottom of the panel...
 
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Old 04-05-11, 07:38 AM
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I will keep the 100A service. I lived in a motor home with 30A service for 10 years so 100A is pure luxury. Plus I'm 63 I'm not going to havering kids and adding bedrooms or great-rooms, spas etc.

I have read that a 100A main breaker can be put in a 150A panel, any input on that? That might be a way to get the 30 space box?

Those Zinsco breakers are expensive, maybe I can pay for the whole job with them! Thanks.

Good catch it is a doorbell transformer, let me guess if I put it in the new panel box the inspector will fail me?
Thanks again JIm
 
  #13  
Old 04-05-11, 09:38 AM
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Originally Posted by jjrbus View Post
I have read that a 100A main breaker can be put in a 150A panel, any input on that?
Yes you can but it's usually more expensive to buy the breaker and panel separately than to just buy the panel kit from the mfr that comes with panel, main breaker and common branch breakers preinstalled.

Those Zinsco breakers are expensive, maybe I can pay for the whole job with them!
Yeah you could sell them, but honestly I think it's better to chuck them. Zinsco breakers and panels are known to be a fire hazard and the longer those things are in the world the more chance of them causing somebody a problem. I don't think it's right to sell them if they haven't been certified and tested by a breaker re-manufacturer. Maybe you could find a re-manufacturer to sell them to instead of just random folks on eBay.

Good catch it is a doorbell transformer, let me guess if I put it in the new panel box the inspector will fail me?
It would be a violation, so he should. You can mount the xfmr to the outside wall of the panel and pass the line-voltage wires through the 1/2 KO to a breaker. The low-voltage wires should not go through the panel at all (so some type of short could not electrocute somebody pushing the doorbell button).
 
  #14  
Old 04-05-11, 04:38 PM
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You could always sell them as a collector's item only. Personally, I would use a QO 30 space panel, but it is expensive. I try to avoid GE,(have one, hate it) but as long as it has a copper buss it is fine.
 
  #15  
Old 04-05-11, 09:10 PM
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A panel with more spaces does make sense. I found a GE TM2010CCU2K 20 space 30 circut panel for $69 is that acceptable? The panel not the price.

Bearing in mind I am not an electrician as I look around I do not see any bond?? wire to the water lines? I thought a wire to the water lines was part of the NEC if they are metal. The lines in the house are copper.

Thanks again JIm 0311
 
  #16  
Old 04-05-11, 09:51 PM
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I was reading this thread so far and when you replace the panel there are two thing you will have to do it anyway one is run a new bonding conductor which for 100 amp service you will need #6 Bare stranded conductor to water pipe before and after the water meter { you will have to make a jumper as well } also the second #6 will go to new ground rods the codes will require it anyway { two rods and be done with it }

as far for the exsting service entrance conductors that is a toss up most case you may have to replace it anyway due some new load centré will be longer.

And you will have to call the POCO to tempory disconnect the power source to replace the load centré and keep in your mind most place will required a inspecton after you change the load centré so please run that by the inspection office first before you do anything with the load centré.

The time to change over will varies a bit but typically take about anywhere from half day to full day depending on what it have to be done.

So plan to have power outage while do the changeover.

Merci,
Marc

Note: I have look at the photo you may keep the exsting main conductors if you go with bottom feed set up most load centré can be inverted { upside down } only if the main breaker is hortzonal handle type if vertical handle then you may have to change the main breaker or order the load centré with bottom feed.
 
  #17  
Old 04-06-11, 07:21 AM
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Thanks for the responses.

Water meter? I'm in SW FL. The water meter is at the street about 100' from the house. No basements here.

The water heater is about 5 foot to the right of panel. I think I have seen panels bonded to the copper pipes on the heater? Wish I had paid more attention.

Everything I see here is run in conduit, do the ground and bonding wires have to be in conduit?

The service entrance wire to the panel comes in through the back, can I drill a hole in the new panel to line up with the existing service entrance conductors?

If I get this done in one day I will be thrilled! The problem with DIY is never having the right parts on hand so three trips to the big box stores and one or two to the electric stores cause the big box stores don't have what you need eats up half the day!

Thanks again JIm
 
  #18  
Old 04-06-11, 07:47 AM
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Best to rent a generator. You need it for power tools anyway. Battery tools just aren't enough at crunch time.
 
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Old 04-06-11, 09:14 AM
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The factory knockout in the back may be close to where you need it.
 
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