Sub Panel Replacement Question - Neutral


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Old 12-19-06, 08:56 PM
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Question Sub Panel Replacement Question - Neutral

I bought a house a few months ago, a first for me, and I have some things to straighten out. Money is tight, so I'm just working on a few things at first.

The house has a 130A main service panel, an old Bulldog "Pushmatic", and a second Federal Pacific "stab lok" panel that was added later, and wired as service equipment.

The service feed to the main panel is 3 wire #0 aluminum SE. There is a common neutral/ground bus, and a #6 copper running to a driven ground rod. This main panel has 3 main breakers - range, dryer, and a 60 amp "main" feeding the rest of the panel.

The second panel (Federal Pacific) is connected 3 wire #8 copper to the main panel, through a short nipple. It is wired as service equipment, with the neutral and ground bonded. It has a total of 5 breakers, no main. The feed wires for hot are connected to the same terminals as the #0 aluminum wire in the first panel. So there's a copper and aluminum wire secured under one screw for each hot leg. The individual strands of the neutral #8 to the FP box are divided at the neutral/ground block in the main panel, and connected to two openings in that block. (There is only one opening in the block, other than for the SE cable, big enough for a #8, and it's in use by the range.)

I don't like this setup. I don't like having a cheap panel as service gear, and I don't like that AL/Cu connection on the main lugs of the main panel. I don't want to replace the whole service right now, because I can't afford it. I'd like to add a new panel as a sub panel, to replace the FPE panel.

QUESTION:

The main panel is old, but looks to be in fine shape. It has two terminals at the bottom labeled as feeds for a sub panel. What it doesn't have is a big enough neutral or ground terminal for a sub panel. Could I use a Cu/Al split bolt to tap the bare Al neutral for a feed for a new panel? (Tapping the SE neutral.) Or could I use a split bolt to tap the SE neutral, to connect to a second neutral/ground bus I install in the main panel, and use this to feed a sub panel? Or is the method of splitting the strands of a stranded wire, and connecting these to side by side ground terminals an acceptable practice? I've never seen that done before. (Ok, I know all of these will work...which is less likely to cause an inspector to say "Are you out of your mind!?")

Sorry for such a long winded question! Oh, and the reason I don't want to just replace the panel is that I'd then have to re-wire much of the house to bring the bathroom, bedroom, kitchen circuits up to current code, install hard wired smoke detectors, etc. I want to do that, but bit by bit, switching things to the sub panel as I go.

Thanks,

Tom
 
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Old 12-20-06, 01:11 AM
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Tom,

The taps you describe feeding the second panel were commonly made to provide additional space for breakers and branch circuits. It seems you inherently understand that there are dangers and shortcomings with the setup you currently have - in your case there are several.

I don't know where your service panels are located, or how they are installed, so the following recommendation may or may not be feasible.

I suggest that you go ahead and replace both panels with a single, new higher and larger capacity service panel. I don't know what your service drop ampacity actually is from the utility transformer, so you'll need to ask your power company if you don't know. You'll need to match your main service breaker with the ampacity rating of your service. Be sure the panel you buy is capable of being upgraded to a full 200 amp capacity just in case you decide to upgrade your service in the future. (Most newer panels are designed to accept either copper or aluminum SE conductors. However, if they are aluminum, you may need to apply a special paste that prevents oxidation, etc. Check the instructions that come with your panel.) Naturally, you'll have to coordinate the change out with your power provider so they can turn the juice off while you make the switch.

For any existing branch circuit cables that are too short to reach the new panel, install a separate j-box (one j-box per circuit) and extend the circuit from that point to the new panel. The j-boxes must remain accessible (meaning they can't be covered by a wall or other permanet covering). If the branch circuit cable reaches inside the new panel but the wires are too short to reach the breakers and/or the neutral/ground bus bar, you may extend the wires by making pigtails using the appropriate size insulated wire and wirenuts inside the service panel provided there is adequate space. Otherwise, you may use the j-box approach.

Be sure to use circuit breakers that are sized in accordance with the branch circuit wiring - e.g., 15A breaker for 14 AWG, 20A for 12 AWG, etc.

This overall approach allows you to take care of the immediate problems you described and positions you for any upgrading you may want or need to do in the future, without having to rewire anything right away. It should also pass inspection.

Best wishes!
 
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Old 12-20-06, 01:57 AM
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Who said that if you perform a heavy up you have to bring the whole house up to current code ?

pull a permit , get rid of the antiques you have and and install a quality cutler hammer or square d panel, there may be a minumum size in you jurisdiction but 150 amp main breaker should suffice , and then contact the power co. to bring a larger service to your home
simple
 
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Old 12-20-06, 09:11 AM
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> Bulldog "Pushmatic", and a second Federal Pacific "stab lok" panel...wired
> as service equipment.

> 3 main breakers - range, dryer, and a 60 amp "main" feeding the rest
> of the panel.

> AL/Cu connection on the main lugs of the main panel.

It really sounds like you have a triple-whammy here. While I wouldn't go so far as to say the Pushmatic panel is a hazard, the split-bus design it has is quite obsolete by modern safety standards. The FPE stab-lok could certainly be a latent hazard, especially configured as a service panel. Moreover, you have essentially 8 main breakers (3 in the pushmatic, 5 in the FPE) which in itself is a major violation and as a side effect has probably exceeded the rating of your service entrance.

I don't see any minor, quick fix; and, I'm not sure that your plan would make the situation any better. I can't imagine the inspector passing any additional jerry-rigging to this already fragile service when the clear solution is to replace both panels with a new service panel.

The only solution I can recommend is that you replace both panels with a new 200A 40 space panel fitted with a MAIN breaker that matches your actual service entrance rating (probably 100A). This give you the ability to add all of the new circuits for your other remodeling projects without the full cost of a service upgrade. This "panel change" would run about 1/2 - 2/3 the cost of a full upgrade. Down the road when you have more funds available, you can then upgrade the rest of the service entrance (meter base, conduit, conductors) to 200A.

Get a few estimates from electricians, and ask what you can do to save money. They may be willing to let you do some of the grunt work to cut down on labor costs.
 
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Old 12-20-06, 08:58 PM
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thanks...

I checked in hoping for a good answer, and instead see three. You're right, trying to patch it would be a hack.

I'll see if I can put in a 200A panel with a 100A main breaker, without having to re-wire the rest of the house at the same time. I'd love to upgrade the service at the same time, but that will have to wait - the SE cable runs through rigid conduit through the house from the roof, and it isn't big enough to run the 200A service cable. I'd have to tear the house apart to replace it. It's a short distance to the pole, so I think I'll go underground with the replacement, eventually.

For the short term, 100A will be fine for me. Oil heat, no A/C, oil HW, and I don't cook well enough to use more than one burner on the stove at a time.

Thanks again!
 
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Old 12-21-06, 10:05 AM
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> I'll see if I can put in a 200A panel with a 100A main breaker, without having
> to re-wire the rest of the house at the same time.

A panel change or service upgrade does not require that you modify any other wiring in the home. It covers only the main panel and its breakers. Some jurisdictions will enforce that you use AFCI breakers for bedroom circuits in the new panel, which can be a little pricey, but you will not be required to update any of the installed wiring in the house.

> rigid conduit through the house from the roof, and it isn't big enough
> to run the 200A service cable.

What is the size of the conduit? A 200A service can be done in 1-1/2" or larger.

> 100A will be fine for me. Oil heat, no A/C, oil HW

Sounds good.
 
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Old 12-21-06, 06:13 PM
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I was worried about AFCI's for the bedrooms, GFI's for the bath, kitchen, and unfinished basement outlets, and the possibility of having to put in hardwired smoke detectors. (Currently battery.) All good things, but a lot at once.

The weatherhead is stamped "1-1/4", but the OD of the conduit measures 2-3/8"...which doesn't sound like 1-1/4 to me. By 200A in 1-1/2 do you mean by using copper? I like the sound of that.
 
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Old 12-22-06, 09:08 AM
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> I was worried about AFCI's for the bedrooms, GFI's...smoke detectors

Usually only AFCI breakers are required for a service upgrade. The GFCI and smoke detectors aren't mandatory upgrades until you remodel the room that the receptacle or detector is in. Local rules do vary, but this is generally the case. You can often avoid installing hardwired smokes by using battery powered, wireless detectors that use radio signals to signal each other instead of a signal wire. GFCI protection can be provided with one GFCI receptacle per affected circuit which are only about $10 each.

> the OD of the conduit measures 2-3/8"

Trade size 2" rigid metal has an OD of 2-3/8". Sometimes just the mast portion of the conduit is 2" RMC to support the weight of the wires if you have a suspended aerial service. The conduit from the meter base to the panel could be a smaller size like 1-1/4. If you can confirm that the entire run of conduit is actually 2", then you will have no problem going to 200A using the existing conduit.

> By 200A in 1-1/2 do you mean by using copper?

Yes, a 200A service can be installed using (3) #2/0 copper conductors in 1-1/2" conduit or (3) #4/0 aluminum conductors in 2" conduit.
 
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Old 12-22-06, 08:13 PM
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I'll be making a trip into the attic tomorrow, with a pair of calipers.
 
 

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