Service upgrade, best approach?


Old 07-06-05, 03:16 PM
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Question Service upgrade, best approach?

I am adding AC to the house and need a total of 70amps in additional circuits. I'm very comfortable doing electrical work.

However, I'm finding myself with a bit of a problem deciding how to proceed. I'm concerned that replacing the existing(old) split buss 150 amp panel with a 200 amp new panel could be tough if the various circuits coming in aren't long enough. In other words, I can't *easily* extend the circuits if they aren't long enough. The other concern involves prolonged power outage, if I need to replace the head and supply lines form the head to the panel, that could take some time.

One option I thought of is installing the new head and supply lines parallel to the existing system, then installing a new 200 amp panel NEXT to the old 150 panel. Then from the new 200amp panel, take a large circuit and supply the old panel, thus making it a sub-panel essentially. This has the benefits of giving me a single point disconnect for the old panel(currently doesn't have one) as well as allowing me to leave the existing circuits wired as is.

I then can add my additional 50 amp and 20 amp circuits for the AC to the new panel.

When the electric company comes out to upgrade me, they can run the poll line to the new head that I added and it's just a matter of me wiring up the old panel(now a sub) to the new.

What do you think? Does it make sense? Is it sound?
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Old 07-06-05, 04:23 PM
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A couple of things to keep in mind.

This would make the existing panel a sub-panel and would require that all grounds be moved to an isolated ground bar. The bond screw would also need to be removed.

The National Electrical Code requires that the length of unfused cable be "as short as practical". The new location may not meet this requirement. You should check with the local inspector.

The grounding system would need to be upgraded also.

You should also check to see if you can do this type of work or if a licensed professional would need to be hired.

If you can do this type of work you would also need to contact the power company to disconnect the power coming into the house. Working this live is foolhardy and very dangerous. Pulling the meter to disconnect the power is not for the untrained and possibly illegal as the meter belongs to the power company. The power company may want an inspection before supplying power to make sure that the installation was safe and Code compliant.

Otherwise the steps are well thought out and would be little different than what a pro would do, except the old panel would probably not be left in place.
Old 07-06-05, 04:46 PM
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Hi PCBOSS, thanks for the reply.

I hadn't thought of the elec. co. wanted to see permits, that is a very good point.

I don't want to leave the existing box in place either, but it seems to be the "path of least resistance" as long as it's not dangerous or "hacky".

You mention "the length of unfused cable" and I'm not sure what aspect you were referring to. If it was the feed from the main panel to the sub, that would be fused in that it would be off a breaker from the main. Isn't that considered fused? If not, I would be interested how I could do this differently.

As for the grounding system being upgraded, what do you mean?

I had planned on driving a new ground bar in, can the two panels share this bar or does each panel need it's own ground bar? I think from your post that you are saying they each need their own bar. If this is the case, do you know off hand if there is an issue with proximity to one another?

Thanks again for the quick reply!

Old 07-06-05, 06:38 PM
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Unfused cable would be between the meter socket and the first overcurrent protection ie main breaker or disconnect.

As far as the grounding you would need to connect within the first 5 foot of were the waterline enters the house, as long as you have a metallic pipe in contact with the earth for at least 10 feet. You would also need a 8' ground rod or two connected to your system also. Bonding any metallic piping in the house would also need to be brought up to Code.

Although it is labor intensive to remove all the cables from the existing panel and re-install in the new panel it is what I would try to do.
Old 07-06-05, 07:04 PM
Join Date: Mar 2005
Location: Central Florida
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I can't quote for some reason, so I'll try to respond to your questions in order....

Almost assuredly, POCO will require a permit for any changes to your service from their end. And your locality may require a licensed electrician perform the upgrade work.

Unfused cable means the cable between the meter and your main panel.

A ground bar is mounted inside a panel. A ground rod is driven into the ground.

Ground rods need to be at least 6 ft apart.

Your current grounding system may not meet current code. What you need to do depends on what you have already. And there are also bonding considerations.

In all honesty, having just completed a DIY upgrade, I'm not convinced that this is something you want to tackle yourself, at least without learning a great deal more about what's involved. Mine went very smoothly, but the only reason I did do it myself was that I couldn't get an electrician in the time frame I required. They're still booked here from the hurricane crossroads last year and the explosive construction in the area.

Have you gotten any estimates?
Old 07-06-05, 08:07 PM
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Hi rodek01,
Thanks for the reply!

I have gotten two estimates, one for $1500 and the other was a "rough" for $1200

While these are not outrageous, it is a good chunk of cash, especially when I consider that the materials would cost me around $300-$400 MAX.

This rather large decision is part of the reason I'm on this message board, I wanted to post my intended plan and see what kind of response I got, if people were very strongly suggesting I hire a professional, then that would effect my decision.

I don't have a problem pulling permits and in my city, the inspectors are available everyday between 5:00 and 5:30 PM to answer TARGETTED questions. So far between the two of you, my page of notes has grown and hopefully after a couple more people throw in their .02 I will be able to make up my mind.

I appreciate your detailed answers. I spoke with So Cal. Edison today and they are sending a guy out tomorrow to tell me what my current service is, I talked to him and he sounds like a nice enough guy, I'll pick his brain and get what info I can.

Thanks again,
Old 07-06-05, 09:12 PM
Join Date: Mar 2005
Location: Central Florida
Posts: 149
I would have jumped on $1500 to have a qualified electrician do mine!!! Yes, my material costs were in the range you mentioned but actually a little higher. Think about it - the old panel goes - the new one is where it needs to be to fit up the existing circuits, you have a fast and safe installation with minimal inconvenience. All at once!

You will need to explore your idea of raising another mast etc with the POCO and the building folks... And you will be working around very live and unfused wiring. Seems like a lot of extra work and a great risk for not much of a return. But that's just my opinion.

By all means, talk to the poco engineer! He will likely know any local requirements also and you can pick his brain regarding the grounding and bonding requirements, as well as masthead and cable clearance etc. Also, explain your plan to him and see what he thinks! BUT remember, the poco doesn't have to comply with the NEC. But it's a start!!

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