Hi All,
My current breaker panel is a Murray Arrow / Hart.
It has two rows of 8 sockets each plus three that are taken up by the main 100 amp breaker.

All of the positions are filled on the panel, I have even removed the old 240v line to use those two spaces for additional breakers.

I have been thinking of adding a sub panel. The house is wired oddly and I am sure that some circuits are overburdened. I want to rewire portions of the house a little at a time to separate things out a bit more logically and keep any one circuit from being overburdened.

Looking at my current panel it says it can use the doubled up breakers which would give me more circuits without the added panel but there are other issues.
The current panel has two lines coming in going to the A and B bus bars and is wrapped by what appears to be aluminum wire which is fed to a common strip on the inside of the box. I assume this means that the aluminum wire is the nuetral. All the circuits are wired so that the ground and neutral lines tie into the same strip as the aluminum wires from the service coming into the house. The box shows that you can add ground strips on each side of the panel and that the large strip on the right would take the neutral wires.

I have heard that some houses were wired this way with ground and neutral run together at the box. I assume that the original fuse panel was swapped out with the breaker box and they left the wiring as it was. The house was built in 1953, was aluminum used then?

Also, since all of the neutral and ground lines are running to the one strip it is quite full. So even if I were to use dual breakers, finding places to wire them in is difficult.

I am in the process of framing a bathroom in the basement and building a shared wall the serves to section off a portion of the basement as a workshop. I will need to rewire the basement lighting and add a few more outlets as well as the circuits needed for the bathroom and several more outlets for the workshop area that can handle table saws, compressor, etc.

So this is really several questions.
1. Should the circuit panel be rewired to separate ground and neutral? I am not sure what/where the earth ground is.

2. If rewiring the panel to separate neutral and ground is there a problem with some circuits wired separated while others still exist tied together or do I have to do all of them at the same time?

3. If not rewiring to separate neutral and ground, can I add another strip to accommodate the additional circuits?

3. Would I be better off adding the sub panel I was originally planning instead of using the double breakers?

As I begin finishing the basement I want to move a lot of the wires so I can put up a ceiling. Some of the wires really look like they should be replaced anyway so I want to run new romex as I go and route it in a better fashion.
In some cases I may just run long lengths of romex where I need them for future use before putting up the walls and ceiling.

Neutrals and grounds only connect in the panel if the Main Breaker is there, neutrals and grounds do not connect in subpanels. The neutral also connects to back back box with a machine screw in main panels, not in subpanels.

Consider changing out the main panel with a new larger one that can use full size breakers. Nothing against the half size, I use them when necessary, but they can cause problems with creating more heat in a small space. Sometimes adding a sub adds insult to injury. A new panel cleans up possible old breakers and connections.

A new panel has more neutral ports, and can even have another equipment ground bar bolted to the panel box on the other side . We will still connect all the greens and bares on the equipment bar, and the whites on the main neutral ba, for consistency and other reasons, but not necessary.

If you do install a subpanel, then move two circuits from the old panel, relocate to the new, for the new 2 pole feeder breaker to feed the sub. Here you must keep the whites on the main neutral bar, do not use the bonding screw into the panel box, and use an equipment bar bolted to the panel box.

Aluminum is popular for incoming feeders and large appliances. Just need to use antioxidant compound on the bare connections and be sure they are tight. Al wire for branch circuits is no longer allowed, if you do have this, then all the connections at all switches, outlets, etc should be treated properly with replacement connections.

Looking at the circuit panel it shows that terminal strips can be added on both sides of the panel for the ground connections and there are holes in the positions where the diagram shows the ground strips so I assume I could install strips in those locations and move some of the bare ground wires to them. Some of the circuits have both the neutral and ground wires tied to a single neutral wire with a wire nut and run to the neutral terminals so it only takes one wire instead of two. I would much prefer to have those connections going to terminal strips without relying on wire nuts which could be disturbed while additional wiring/rewiring is going on.

I would prefer a new larger panel be put in place but I think it would be costly to pay someone to do it and move all the old connections over. I do not believe I have an outside breaker to shut off the main power to the circuit panel so I would not even consider attempting it myself.

I think adding the additional panel would be my best bet for now and it gives me a safer location to work as I add new circuits since I can kill all power to that box from the main panel. It would make me a LOT more comfortable.
I am very familiar with what it takes to make good electrical connections but I have a healthy respect what electricity can do and getting anywhere near the live feeds at the top of the circuit panel makes me nervous which I guess is a good thing. :)

How is the neutral connection generally made to the sub panel? Just run the same gauge wire from the neutral strip to it as would be approriate for the breakers feeding the hot lines? No independent ground needed?

If I remember correctly, it appears that to add terminal strips to the main panel I would have to drill into the cinder block wall the box is mounted to since the holes in the panel are flush to the wall. What would be an appropriate connection to assure these strips are sufficiently grounded? A heavy gauge wire to the neutral strip?

Lastly, before I decide completely to add my own sub panel, is there a good online resource to help me determine my consumption needs so I can tell if the demands will be too high for the 100 amp service I have? Something that gives general information for various appliances so consumption can be estimated would be helpful. Many appliances I should be able to look at to find their requirements but not all.

Thanks again for the information. I do a lot of research before starting any project like this to make sure I have the bases covered and preliminary research always raises more questions so I keep going to I have the full picture in my head before I begin.

Oh, I forgot to mention it.
I do not believe any aluminum was used in the wiring inside the house, just on the main service coming in at the panel. Rather than having two large hot lines and a large neutral the two hot lines are surrounded by heavy gauge stranded aluminum which is then tied to multiple points on the neutral terminal strip.

This brings up another related question.
I can shut off the main circuit breaker so the panel is not live except for the main lines at the top of the breaker but this does not affect the neutral.
Since the neutral is tied to ground does this mean there is no risk of shock touching the neutral buss or wires as long as the main switch is shut off?

Thanks.

OK I understand the ease of adding the sub panel. Shutting off the main will de-energize all the main panel except the feed wires into the main breaker.

Replacing the panel is more involved, and requires the meter to be pulled to de-energize the main lines. This would need to be done with an electrician, and probably involve the utility company.

You will also be able to work on the neutral with the main breaker off. Normally the neutral can be touched even when the power is on, but let's leave that to the professionals. Laypeople should treat the neutral as a live wire.

The neutral to the sub panel needs to be of the same size as the live feeders to the sub panel, say for example, you use a 60 amp feeder, then you use two #6 wires, labeled black and red for the hots from the 60 amp breaker, another #6 wire labeled white for the neutral, and, yes, you also need a separate green equipment ground from the main panel to the sub panel. Remember, the grounds and the neutrals must not be connected in any fashion in the sub panel.

Running a #6 green from the main neutral bar to the added equipment ground bar in the main panel will be sufficient, in addition to bolting the bar to the panel with machine screws.

Usually the main panel is mounted on wood, and not directly to masonry, so you may need to drill through the metal into the masonry to create space for a screw. Also, do not mount the equipment bar with sheetmetal screws. Only threaded machine screws. Sheetmetal screws are not allowed due to causing a poor electrical connection. So you will need to tap out the holes in the metal for machine screws.

Isn't this fun? There are so many little details that most people just don't realize about electrical work, code even dictates the type of screw that must be used, and all for very good reasons.

Every appliance should have a nameplate that lists the amp or watt load. Any general information you find will be just that, general.

Performing calculations to size services is another story. To be consistent, I will not explain how to do these calcs here, too detailed and too many variables to explain. I tell everyone if they want to see how to do the calcs, find a NEC code book at the library and their you can review. If any one else wants to explain, be my guest.

If you give me the total square feet of livable space, not including any unfinished basement, crawl space, attic, and garage, and list all the appliances, including type of heat, and I can do the calcs for you.

You will be checking with your local building official to be sure you can perform your own electrical work, and apply for a permit and have the work inspected? Most states, if not all, allow homeowners to wire their own, single family homes only.

I do not yet know what the local regulations are, I have to look into it.
Are these generally state regulated or local City/Town?
If it goes by state you might be able to tell me as I live in Western Mass and I see you are from New England.

For the calculations do you take everything into consideration such as non-permanently wired lights, fans, computers, televisions, etc?
The furnace, water heater and clothes dryer are all gas, and the washing machine was just replaced with a high efficiency front loader so that does ease up on current demands. We have a small portable spa that runs on 120v but it is a low power circulator pump so the only serious current draw is from the heater element.
I am a computer guy so the house is rife with them. At any given time at least three computers are running, sometimes four but three of the four use LCD monitors. Other than lighting the rest of the larger draw items would be the electric range which is a 1 year old model, refrigerator, new upright freezer and air conditioners of 5000, 10000 and 12000 btus. Only the 12000 is used commonly during the daytime when the weather is hot and humid, the smaller ones are used only at night in the bedrooms when open windows do not provide enough cooling. I am contemplating a whole house fan to exchange air with the outside in the evenings when it starts to cool down and to help force the hot air out of the attic to lessen the heat radiation into the house so it can stay cooler and we can avoid using the AC as often.

I will have to start going through the appliances and getting their info but it could take a while to get everything if I need to look at things like the ceiling fans, Tivo boxes, DVD players, etc. I am not sure if the calculations include everything we are likely to use or just hard-wired items and things that are used on a frequent basis such as televisions and computers.

Thank you very much for your help. As I said, I research things thoroughly before beginning the work. I have a lot of experience with wiring, just not house wiring. I used to build televisions transmitters, medical test equipment and a whole host of other items so I know how to wire well and safely but more towards the appliance side of things rather than service so I am being careful to make sure I understand everything on that side. And I still have a lot of information to find out for local codes for the routing of cables, placement of outlets, number of outlets allowed on a circuit, etc. But those are all things I will research when I get to a point in the projects where it is needed.

Thanks.

Mass is similar to Connecticut and Maine, which I am very familiar with both, all are very strict. The permit will be a local city,town, or maybe even county. The ordinance is issued by state legislature for the local jurisdictions to follow.

As an example, I found and attached a permit at the state website that refers to homeowner doing their own electrical work.

You do not need to get the load of every little dodad you have, only list the major fixed and stationary appliances, which appears you have given me.

What I really need is the total square footage of the livable space, and do not include the unfinished basement, attic, crawlspace, or garage.

The box hardware stores sell how to books that explain the little details with photos on how to do basic wiring, and most I have seen are really very good.

Before starting any work, make an appointment with and go meet your local electrical inspector. You will find that he/she will be very helpful, inspectors are good people too. Beware thou, inspectors will tend to look much more closely at a homeowners work than a contractors, since a contractor should be much better at all the small details, notice I said "should be".

Also, be careful how you ask an inspector for information, they are allowed to quote code, but will not tell you how to do the job. Ask the wrong question or in the wrong way, and he will pick up that you do not know how to do something, and it may be your downfall.

Although ,there is an inspectors joke/saying I get a kick out of goes like, "Arguing with an inspector is like wrestling a hog in the mud, after a while you realize the hog loves it"

Going by memory I made a rough sketch of the house with what should be fairly close dimensions and came up with an approximate 1,200 square feet living space. It is not a large home but gains extra space from a family room extension off the back.

I have books and have read numerous web sites about various bits of wiring and internal construction and it all seems pretty straight forward. I have a book my wife gave me for christmas on the electrical code and just have to find out what modifications apply for my area.

The less obvious bits of information that most of the books do not supply is where I will have to spend more time. I want to build walls in the basement and will have to move a lot of electrical that runs across the bottom of the floor joists. In most cases the walls will be spaced off the cinderblock wall anyway leaving a convenient area for wire to run behind it so that it is out of the way so a ceiling can be put up and still accessible. I just have to find out any rules about bundles of romex going through the area, how it should be secured, details about going through wall and floor joists when necessary, anything that may relate to fire prevention, etc. The books and web sites all talk in simple terms about a narrowly scoped task that may be more complicated when considered along with other aspects of my projects.
I want to make sure I know what I am talking about before talking to an inspector and I absolutely want to know I am doing it the right way before they come in and inspect the work. I have a fear of getting a hard-case inspector nitpicking me to death just because he can or because he is fed up with self-improvement types and thinks we should all just pay someone else to do the work. If I had to pay others the work would not get done until the kids are out of college and living on their own with well established careers.
The few times I have had to pay someone to come in to do work I feel I got raked over the coals. A plumber who put in a T on the gas line to run a pipe down the wall for the gas dryer charged me 4 hours for his labor which really took about an hour and he charged me the same rate and another 4 hours labor for his teenage assistant who only stood and watched him work, never actually participating.

I will have to look over the application in detail. I had one a few years ago when I had to replace the roofing but my wife had gone down and gotten the application and they helped her fill it out there. :)
Franklin County is the next county over, I am in Hampshire County but the permits are probably identical or at least very close. I will look them up online and do some reading.

Thanks much.

Seems like you have a great attitude, and are asking the right questions. Don't be too shy of the inspector, yes he may look closer, but will be reasonable, he will be pleased that you are a DIY and applying for a permit and asking questions.

If you install some sort of suspended ceiling will help with the wiring attached to the bottom of the framing. Also will be helpful later should you need to add or repair any mechanical above the ceiling.

Try not to bundle more than 2-3 cables, any more you will run into derating the ampacity of the cables, and that is another issue.

Based on the sq ft, and the appliances, and having gas for the typical large appliances, you theoretically can use a 40 amp service. The smallest service allowed in a residence is 100 amps, so you will have plenty of power. In the event , for example you add a hot tub with a 50 amp load, then that's the max, any more you will need a 200 amp service.

Have fun with this, read up, get back and ask questions. If you get the chance, if you know of someone having a home wired or added by an electrican, see if you can take a look at how they do things.