When to Rewire

[PastorPaul]

Our new home was rewired a few years ago, but they only put in a 100 amp service. Since I will have my shop, and we hope to add a master suite and a dining room, I plan to upgrade to 200 amp. My question is, should I do it immediately (meaning as soon as the temperatures are warm enough to work in the garage), in order to provide extra power for the shop, or is 100 amp enough for now? The house is 2 bedroom, kitchen, living room, utility room, partial basement, and a mud room. The attic and crawl space are also lighted. The dryer central air are 220v, and I think there was something else. We have a freezer and an extra refrigerator, plus if the gas range ever goes out Mary will probably want electric.

With the shop going in, should I go ahead and upgrade right away, or just wait until I am ready to insulate the garage and do it before I close in those walls? I realize that I won't have all the tools running at the same time, but I will have a drill press, band saw, surface planer, router table, and a 220v table saw.

Lowe's has a 200 amp Square D box with most of the breakers we need for about $120, so I might be able to sneak it in right now. If the orginal matches, I can use some of those breakers as well.

How about some opinions as to whether I should make the change now, or wait until it becomes a have to do project.

Pastor Paul
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"If they don't have woodworking in heaven, I ain't going!!!"

[dicklaxt]

A 100 amp service will carry you even after your upgrade,, post a list of all you loads and number of receptacles and I'll show you why

dick

[TDHofstetter]

Hey, Paul.

The last house Lo & I lived in had three bedrooms, one bath, a monster swamp cooler, two refrigerators, a chest freezer, a 1-horse water pump, and a garage-cum-woodshop. The whole place ran out of a 65-amp breaker box.

I think you'll be fine for now - and quite possibly for the future - as long as your present breaker box has a couple more places for shop breakers. Maybe just one. Maybe the one that feeds that area is plenty.

-- Tim --


You can always take one more step against the wind.

[Lou_williams]

Paul,

I would love to have 200 amps for my house but, I have 100 amp service. Now here is my house 3000 sq ft, with 5 bedrooms and an office. Electric double oven and cooktop. Electric dryer, and my full shop all on that service. I don't need air, but I have one of the largest Refergerators and a freezer.

Shop most of my stuff is 220, 2 HP bandsaw, TS, DC, 5 hp Compressor, 3 hp shaper, and combo Jointer planer. And a 50 amp Arc welder. I also have a computer network of 6 computers, two network printers and all the network gear. Now I can't run everything at the same time. But, since I can't be in two places at the same time it has not been a problem. For me to upgrade the service would be a big pain in the rear. I have two subpanels off of the orignial main panel and that has worked for me.
The second sub panel has some of the shop stuff, my lighting is in the main, and all the other shop stuff is in the first sub panel.

So for your home as long as your air and heat are not too much of a load then you should be just fine

[Tom D]

I presently have a 200 amp service box, with freezers in the cellar and a good sized shop, a 3 bedroom house with all the electrical appliances, my box is still half empty. I think 100 amp would be plenty.

[PastorPaul]

We just got back from our weekend away, and spent this evening moving a few things in and measuring rooms. I checked the panel and there is no room for expansion. Can I run a sub-panel off the main to give me breakers for the shop? There are lost of 110 outlets, but I could find no 220 in the shop. That's why I thought this might be the time to upgrade, to get the extra spaces for breakers.

There is one thing strange in the shop. It looks like it might be a sub-panel, but it is entirely closed in. On the left side is a series of what first looked like knockouts for breakers, but they are too small. I guess I'll have to open it to see what is inside. If I can find the time tomorrow, I'll shoot a digital photo of it and post it here to see if someone can identify it.

Pastor Paul
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"If they don't have woodworking in heaven, I ain't going!!!"

[milanuk]

I've got about the opposite situation. Bought the house two years ago, and the bits and pieces I've ran into along the way have me dreading working on the electrical circuits here (and my background is in electrical motor controls and generation!). Basically I have a 3000 sq ft house w/ a 200A service, and the service panel is *full*. Only about 2/3 are actually labeled, and judging by some other things I've ran into in the place, I'm not holding my breath on the accuracy of the ones that are labeled. The shop is on a 240v/30A bkr, fed w/ 10/3 underground almost 200' to the shop. Right now, my rough guesstimate of the lighting and other misc. loads (extra fridge and a chest deep freeze) in the shop, I might be as much as half-ways to full on that ckt capacity-wise already, w/ no major tools like tablesaw, dust collector, jointer, planer, etc. The voltage already drops 10%+ and the lights dim just when I start a circular saw, router, or miter saw.

I'm at the point where I need to dig thru the main service panel, and figure out which circuits are redundant (I've found three 20A ckts running to three duplex outlets w/i 6' of each other so far) and how much capacity I'm *really* using, and if I can afford, electrically speaking, to upgrade the service to the shop to a 40 or 50A sub-panel, w/ 6/3 or so.

Ain't houses fun?

Monte

[milanuk]

You might be able to put some of your more lightly used ckts on slimline breakers, where 2 20A slimlines fit in the space of one conventional 20A bkr. Of course, you still need to have the electrical capacity available to pull this off safely.

Monte

[PastorPaul]

Monte,

Thanks! I hadn't even thought of the slimlines.

Pastor Paul
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"If they don't have woodworking in heaven, I ain't going!!!"

[TDHofstetter]

Oh, man, Monte - I don't envy you that job. Been there & done that, and it is a royal PAIN!

Reminds me of that TV commercial for cellphones.

"Can you hear me now? Good!" :)

-- Tim --


You can always take one more step against the wind.

[PastorPaul]

The last few days, I have been working with adding lights, changing outlets, etc. The description of the breakers on the door panel, don't match the tags put on the breakers themselves. It is a real chore to figure out which breakers actually go to which parts of the wiring. For serious lack of space, I think I have to go with the 200 amp panel. The slimlines may not free up enough room.

When I start insulating and drywalling the shop, I'll probably rewire the garages. There are extension cords wired from receptacle boxes, with light fixtures wired into the extension cords. The biggest problem is that one wall is one massive storage unit and small workbench. Working with that wall will take some doing. But heck, I've got time on my hands now -- once I finish unpacking and the honey-do list.

Pastor Paul
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"If they don't have woodworking in heaven, I ain't going!!!"

[TDHofstetter]

Wow, Paul - have you ever considered switching to DECAF? :) :) :)

Just to toss in another option to keep you confused, you might consider putting in a "daughter" subpanel instead of replacing the entire breaker box. That'd take far less doing, and not necessitate flumping the power to the whole house until you can move all the circuits to the new box. You could just pop the new box in, power it from a breaker pair in the old box, then transfer circuits over to it one by one... adding new ones at will, of course.

Not sayin' you GOTTA do it that way, of course - it's just a thought.

-- Tim --


You can always take one more step against the wind.

[PastorPaul]

Tim,

The service panel is located in such a way that changing it out will be a snap. I'll take one day, pull the cover off, and identify and mark the circuits (I suspect that a couple of circuits are piggy-backed on indivual breakers). Then I'll get up early one morning, have city utilities pull the meter (the drop is already heavy enough for 200 amp), pull the old service panel and install the new. I'm going to have all my duck in order before I begin, so I don't have to take more than one morning to make the change.

Pastor Paul
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"If they don't have woodworking in heaven, I ain't going!!!"

[TDHofstetter]

Sounds like fun, at any rate.

Oh, be SURE you have flashlights handy... MORE THAN ONE. Been there. :)

-- Tim --


You can always take one more step against the wind.

[PastorPaul]

OK, Dick. It took me a bit to get around to it, but here is what I could gather for you. Items in bold are plugged into receptacles. I don't know if you need that information, and some of it would be evident, but I wanted to give you as much information as possible. I also realize that not all electrical items will be plugged in and in use at the same time, especially where the shop is concerned, but I wanted to give you the best picture I could.

Office: One ceiling fan with light. 2 duplex receptacles on opposite sides of the room; one with a night light, the second with a power strip feeding two computers, two printers, one scanner, computer speakers, calculator, desk lamp, clock radio, computer lamp, one dial-up modem and one cable modem. Eventually, after I have converted my Mac files to Windows, one of the computers will be eliminated and a typewriter may take its place.

Bathroom: One light fixture, one exhaust fan/light combination, one night light. One duplex receptacle.

Hallway: One ceiling light.

Living Room: One ceiling fan/light, two swag lamps, two table lamps, electric fireplace, cordless phone, answering machine, power strip feeding TV, VCR, rewinder, stereo receiver, cassette deck, turntable, and Nintendo game. Four duplex receptacles.

Kitchen: One ceiling fan/light, two fluorescent under the cabinet lights, dishwasher, refrigerator, microwave oven/range hood, TV, VCR, coffee maker, can opener, toaster, oven clock/timer. Eight duplex receptacles.

Laundry Room: Ceiling light, washer and electric dryer. One duplex receptacle. One 240 receptacle for dryer.

Rear Hallway: Two ceiling lights and one night light. Three duplex receptacles.

Breezeway: One light, refrigerator, and upright freezer. One duplex receptacle.

Master Bedroom and Closet: Ceiling fan/light, TV, VCR, CPAP breathing machine, one pole lamp, two reading lamps, clock radio, rechargeable razor, and wall light in closet. Three duplex receptacles.

Half Bath: Light and fan, both plugged into a switched duplex receptacle. Night light. Two duplex receptacles; one switched, one hot.

Attic: Three or four lights and three or four duplex receptacles (I wasn't going to fool with the ladder to find out for sure).

Crawlspace: Three lights.

Basement: Three lights, furnace and A/C unit, electric water heater, and dehumidifier. One duplex receptacle.

Single-car Garage: One fluorescent shop light and garage door opener. One exterior receptacle (if you can call an interior receptacle mounted under the eve exterior) for RV hook-up. Two duplex receptacles mounted in ceiling.

Double-car Garage and Shop: One 10" table saw (wired for 240v, but not wired up yet), five fluorescent shop lights, two incandecent lights, ceiling fan/light, clock radio, garage door opener, dust collector, two shop vacs, rechargeable weedeater, drill press, bandsaw, planer, router table, charger for electric scooter, two chargers for cordless drills, hand-held plunge router, detail sander, finish sander, random orbital sander, electric stapler, three corded drills, soldering gun, soldering iron, sabre saw, oil-filled radiant space heater, jig saw, and portable air compressor. Eight duplex receptacles in the walls, four in the ceiling.

Here is how my service panel looks:

100 amp main.

1 - 20a South Garage Wall Receptacles
2 - 20a East Garage Wall Receptacles & Openers
3 - 20a Garage Lights
4 - 20a Kitchen, Back Porch,& M. Bedroom Lights
5,7 - 30a, 240v Washer & Dryer
6 - 30a Outside RV receptacle
8 - 15a Basement & Front Porch Lights, Living Room Outlets, & Attic Fan
9, 11 - ?a 240v Mainline to Basement, Kitchen, Furn. & A/C
10 - 15a North Kitchen Wall Recept
12 - 15a Office, Bathroom, and Living Room Lights

9 and 11, which have no amperage markings, run to a sub-panel in the basement with the following:

30a 240v Dryer, 30a 240v A/C, 20a Kitchen Outlets,
20a Furnace and Bedroom Lights.

Though #6 has a 30a breaker for the RV hook-up, it is run with only 12-2 with ground. Seems pretty light wire for a 30a breaker.

Dick, now that I have thoroughly confused you, what do you think? Can I still get by replacing 2 & 4 and 8 & 10 with the mini-breakers and add my 240v breaker for the table saw? Any other things you see that need my attention?

Pastor Paul
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"If they don't have woodworking in heaven, I ain't going!!!"

[Lou_williams]

Paul,

I think a new panel and lots of breakers and circuits is one questiona and the total service is another. I think you can stay with 100 amp service. Just to give you a heads up my house is 3000 sq ft. 5 bedrooms, 3 1/2 bath, office, living room, family room, Kitchen, upstairs laundry, and my shop. Lots of big power hungry tools. Almost all of them on 220 circuits.

My whole setup is on 100 amp service and my shop is off of a 50 amp sub panel.

Now if you want to upgrade you panel for lots more breakers then go for it. That is one thing I just might do. My orignal panel is not a good brand and has some major issues. I don't think you have to get new service for your place at all.

Now that 30 amp breaker needs to have a min of #10 wire on it that is a fire hazard. You could also resize the breaker to 20 amp and be just fine.

My home has 7 or 8 computers running, two laser printers, two inkjets, scaners, cd-r's, sound systems, 6 tv's, electric oven and stove, No AC. But my compressor is a 5 hp continous runing on 220. I also have electric dryer that is going almost full time. I have 3 dancers living in my house and they change about 5 times a day.

[PastorPaul]

Lou,

>I think a new panel and lots of breakers and circuits is one
>questiona and the total service is another. I think you can
>stay with 100 amp service. Just to give you a heads up my
>house is 3000 sq ft. 5 bedrooms, 3 1/2 bath, office, living
>room, family room, Kitchen, upstairs laundry, and my shop.
>Lots of big power hungry tools. Almost all of them on 220
>circuits.

Sounds like you have LOT more than I have to worry about. Makes the 100 amp serice sound OK.

>My whole setup is on 100 amp service and my shop is off of a
>50 amp sub panel.

Since my shop already has about four circuits, and I am going to add a breaker for the table saw, I could just use the slim-lines I had discussed or, instead of putting in the saw breaker, put in the sub-panel you mention and run the saw off one of the breakers in the sub-panel. (BTW - What size breaker should I use for the table saw? It is either a 1 1/2 or 2 HP.) That would also take the shop breakers out of the main box and free up those breakers for other use if needed. Do they make fillers to slip over blank breaker holes, or should I just leave a disconnected breaker in there and leave it in the off position?
>
>Now if you want to upgrade you panel for lots more breakers
>then go for it. That is one thing I just might do. My
>orignal panel is not a good brand and has some major issues.
> I don't think you have to get new service for your place at
>all.

That sub-panel, combined with a few slim-line breakers, could gain me up to 6 new open breakers.

>Now that 30 amp breaker needs to have a min of #10 wire on
>it that is a fire hazard. You could also resize the breaker
>to 20 amp and be just fine.

We don't plan to ever own an RV and need that outlet, so I plan to re-run the wire that is there to give me two exterior weather-proof duples receptacles; front and back of garage for being able to reach most of the yard. I'll use either a GFCI breaker, or two exterior GFCI duplex receptacles. I've heard pros and cons to both way to go, so I am not sure which is best. Of course, that 30 amp breaker has to go.

>My home has 7 or 8 computers running, two laser printers,
>two inkjets, scaners, cd-r's, sound systems, 6 tv's,
>electric oven and stove, No AC. But my compressor is a 5 hp
>continous runing on 220. I also have electric dryer that is
>going almost full time. I have 3 dancers living in my house
>and they change about 5 times a day.

I'm confused! How many amps do the three dancers draw and does their changing five times a day affect that? Are they all on the same breaker, or individual ones? :P

Pastor Paul
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"If they don't have woodworking in heaven, I ain't going!!!"

[Lou_williams]

>Since my shop already has about four circuits, and I am
>going to add a breaker for the table saw, I could just use
>the slim-lines I had discussed or, instead of putting in the
>saw breaker, put in the sub-panel you mention and run the
>saw off one of the breakers in the sub-panel.

Yes, you can go ether direction. You will need to use a 220 double breaker if your going to run the TS on 220. That means you have to make space for two full sized breakers.

(BTW - What
>size breaker should I use for the table saw? It is either a
>1 1/2 or 2 HP.)

At 220 a 20 amp 12 guage circuit will give you all the power you need.


That would also take the shop breakers out
>of the main box and free up those breakers for other use if
>needed. Do they make fillers to slip over blank breaker
>holes, or should I just leave a disconnected breaker in
>there and leave it in the off position?

You can go ether way but the easy is just to leave a blank breaker in the slot. Then you can use them for some other project. Remember you will need two slots for the new 220 breaker (50 amp) to feed the sub panel. So it will free up two slots for other things not 4 from your shop sub alone.

>
>That sub-panel, combined with a few slim-line breakers,
>could gain me up to 6 new open breakers.
>


>
>I'm confused! How many amps do the three dancers draw and
>does their changing five times a day affect that? Are they
>all on the same breaker, or individual ones? :P

Well you would have to know my daughters to understand that they are the largest load in the whole house. One example, I just set up the 6 VCR's that I will need starting next week to make a hundred copies of the video's from this weekends spring concert. We record the show with a 3 chip digital recorder and duplicate it for the customers to buy a video of little susy dancing. Now it will take me about 2 weeks to dup all those tapes and that will have the VCR's going full out. I also have a power amplifier to make sure the signal is good to all the recorders.

you have never seen power use like my house and it all is of 100 amp main.

I forgot the arc welder that has it's own 50 amp breaker. But it doesn't get fired up often.

Lou

[PastorPaul]

>
>You can go ether way but the easy is just to leave a blank
>breaker in the slot. Then you can use them for some other
>project. Remember you will need two slots for the new 220
>breaker (50 amp) to feed the sub panel. So it will free up
>two slots for other things not 4 from your shop sub alone.
>

Lou,

Taking the shop breakers out of the main panel will open three slots, but that will be reduced to one after the breaker is installed for the subpanel. I have four other breakers that I can combine into the slim-line, freeing up two more slots. That will leave me with three open slots, which can be six new circuits using the slim-line breakers, but the only expansion beyond the shop subpanel I plan is the future possibility of an electric stove. If the LOML gets used to cooking with gas, I won't have to worry about that one. Oh! Let me take that back. If we add our two rooms, that will require a couple of extra circuits.

Pastor Paul
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"If they don't have woodworking in heaven, I ain't going!!!"

[Greg M]

Howdy all,

I think this is my first post as an actual member although I have posted some questions in the past as a guest and have been lurking in the shadows for quite some time learning from all the wonderful advice found on this forum.

This has been a fairly lengthy thread and I think I have skimmed it all, but I don't remember seeig anyone make the following point: IT IS VERY VERY VERY DANGEROUS TO BE MESSING WITH AN UPGRADE OF YOUR MAIN SERVICE PANEL and any upgrade of the main panel should be done by a qualified electrician. The main power lines coming into the main service panel from the electric company are ALWAYS HOT and you have no way to turn them off. That means you will be handling 100+ amps of hot electricty when installing a new main service panel. This is very dangerous. Also the wire from you meter to the main service panel may not be of sufficient guage to handle more than the current 100 amps you have at your main service panel, so merely puttign in a 200 amp panel may not be all the work that is required for the upgrade.

This is not a problem when installing a new subpanel as you can shut off the main breaker in the service panel before installing a new breaker for your subpanel and running the necessary wire.


Be safe,

Greg M.

[PastorPaul]

Greg,

Not even an experienced electrician will work on a hot main coming in, if he has any sense at all. The electric company comes in, pulls your meter, then your mains are dead. Some electric companies will let you pull your own meter, but those I have dealt with prefer to have their men do it. If a meter isn't pulled, or put in, just right it can blow the meter.

After you have your new breaker box installed, you can have them put the meter back. Personally, I normally don't have them do that until I have finished putting all the circuits back and have done a full continuity check on the whole house, even though this isn't necessary if you mark your circuits as you take them out of the old box.

Also, our electric company came out already and verified that everything, from the transformer on the pole right up into the breaker box, is of ample size for 200 amps already. In studying up on my breaker box a bit, it looks like I could actually replace the main breaker assembly with a 200 amp assembly and leave the box and the circuits as they are. It is the first box I have seen where this can be done, but it's also the first time I have looked at that option, so maybe all boxes are that way.

In either case, if the 200 amp main assembly isn't much of a savings over a new box ($120 or so for the box, main breaker, and most of the breakers I will need), it makes more sense to replace the whole box and get the added space for additional circuits for future expansion.

I know that my circuits are pretty well set up (as much one can without turning on everything in each circuit and doing an amprobe test). I just didn't know if my main breaker was large enough to handle the whole house (I don't know all the formulas for calculating that stuff), and I didn't know if a sub-panel was the way to go with the shop, or if just using a few slim-line breakers to give me space for one more 240v breaker was the better choice.

Part of what I have to deal with is incorrect wiring already in place. 12-2 w/ground and 14-2 w/ground come out of the breaker box, but I have found some of the circuits where the ground is not carried throughout the house. Why someone would buy the grounded wire and grounded receptacles, and then not use the ground wire, is beyond me. In some cases, I can attach the ground wire at each box. In others, it was cut too short to even get a pigtail on it. Also, as I mentioned in one of my previous posts, one circuit is wired for 20 amp, but has a 30 amp breaker. It isn't hard to figure that the weak link in that chain is the wire.

I've been doing wiring for years, having learned the mechanical part from three brothers who were electicians for umpteen years. I just never learned the theory. When in doubt, I grab the NEC book.

Pastor Paul
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"If they don't have woodworking in heaven, I ain't going!!!"

[Greg M]

Good to see that you have a firm grasp of the situation. I wasn't sure of your skill level with this type of project, but from your post I can see you are well experienced. I didn't go into the whole meter pulling electric company shutoff stuff because I didnt want to convolute the safetly point I was making (I was tryign to scare you into not trying the project, because this is way to complex/dangerous in my opinion for a novice. Knowing your skill level now, I say by all means go for it and save a lot of $ doing it yourself). You are, of course, absolutely correct, no electrician will work with a live main and the electric company will always have to be involved to shut off the line to your house/pull meter/replace meter. It's nice that you are already setup from the pole to your house for 200 amp service.

If you can swing it monetarily, you'll probably be happier with a new box with room for the future.

Best of luck.

[PastorPaul]

Greg,

The 100 amp service is fairly new (3 or 4 years, I think). I just learned that I can have more circuits than I previously thought. GE actually makes a double pole (220/240) slim-line breaker that takes the space of one single pole.

Originally, I thought I would have to take out four single pole breakers, replace them with four slim-lines which would leave room for a standard double pole. Instead, I can take out two of the singles and replace them with two slim-line single pole breakers and one slim-line double pole breaker.

I have to check it out, but I assume that I need to put in one single pole slim-line in the first half of space one, with the double pole slim-line spanning spaces one and two, and finally filling out the bottom half of space two with the other slim-line single pole.

If a 100 amp main is enough for our needs, the slim-lines will give us plenty of options, without the cost of a whole new box. Of course, the way the box is located, I can easily upgrade to the 200 amp box in the future.

Pastor Paul
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"If they don't have woodworking in heaven, I ain't going!!!"