There are a bunch of things that don’t draw that much power, but are recommended/required to have their own 20 amp circuit. A fridge may only draw 5 amps, but needs its own circuit. Go for plenty of slots even if the electric company limits how big of a main breaker you can have.
I like to see a light or something you will notice on the circuit with a fridge or freeze. If the breaker pops due to a storm or surge, you kinda want to notice it is off before the carrion vultures start circling your house.
the utility will run a new wire overhead to match your new service if it is needed. if you put in a 200A service and the old wire from them is less, then they will replace their wire to you. they like to rent you electrons.
the electrician will put in a service drop (conduit/cable to outside) to match your breaker box. the utility will run an overhead wire to that for its capacity.
Back in 1994 (post Northridge earthquake) since I had to change out my furnace and damaged duct work anyway, I decided to put in central air. So I put in a 100A service to replace the 60A that the house was built with.
Fast forward to 2005, I want to add a spa to the back yard.
Guess what? Had to rip out the 100A service and put in a 200A service.
:smack:
My advice? Put in the larger panel.
As the others said, just get the 200amp box. You don’t have to use it all, but if you need it someday, it will be there. The big cost difference may not be the box though. If you have to upgrade the exterior wires to the pole it can get expensive for all that copper. If your utility pays for that wire, then definitely go for it.
I can’t really tell you if the price is reasonable in the SF Bay area, but a new breaker box, outlets, a light switch, and a few new wires for appliances shouldn’t take more than 2 man days. The wire for the dryer could get expensive if it’s not close to the box. But $4500 sounds expensive to me.
On the other hand, you didn’t provide a detailed list of parts, and you mentioned bringing the wiring up to code. So there may be some existing wiring that has to be gutted, and new wires installed in tight locations, and maybe there are a lot of outlets, and you want the designer version instead of the basic ivory, and he has to install a new ground post and lightning protector, and then there could be a complicated permit and inspection process eating up time, sometimes just to wait for the inspector, and before you know it, $4500 may be very reasonable.
I hope you are using 12/2 with ground and not just 12/2.
If I was changing out the main on any house over 1000 sq ft I would go with 200 amp. The difference between 100 and 200 should be only a small percentage more. The utility may have a problem and want to limit the increase but check with them.
My reason is simple. Energy use is homes is going up every year. At one time homes had one TV. today several enertainment centers. Better to over build today then to be limited or have to upgrade again.
Example through the years. The old ranch house where I was born orgionally had a 30 amp service. It worked for many years. The oil fired water heater was replaced with a electric heater. A three way kife was put in so only one of the electric cook stove or the electric hot water heater could be energized at a time. After time my Dad upgraded to 60 amps. worked well until around the 70’s. Kept cooking the fusses until PG&E refused to read the meter. By condeming the main fuse box my brother upgraded to 100 amps. By the time he sold the rance house he was considering going to 150 amps.
When I purchased my first house 60 amp main in the late 70’s. This house was 100 amps the listing listed it as an extra. Today new homes come with 150 to 200 amp mains.
Look at the total cost between 100-150-200 amps then make your descision.
12/2 is two 12 gauge wires with a ground by default. I don’t believe you can actually buy 12 gauge Romex that lacks a ground anymore. You can buy 10/3 and 8/3 for older stoves that lack separate grounds, but I don’t believe 12 and 14 gauge NM wire for branch circuits is even sold without a ground wire. I know I haven’t seen any since I was a kid.
The practical difference between a 200 amp panel and a 100 amp panel ends up being much more mundane then the amperage, a base 200 amp panel has more breaker slots then a base 100 amp panel. Newer codes require more dedicated circuits. While the amperage draw on those may be minimal you still need physical slots for the breakers to fit. Figure a 100 amp panel has 20 slots, and a 200 has 40.
Figure to meet the most basic requirements you’d need 15 slots. If you want to do fancy(practical) stuff like have each bedrooms outlets on their own circuit or not having all your lights on the same circuit you run out of spaces in a 100 amp panel.
You can get 100 amp panels with more slots or add a sub panel to make up for missing slots but then you are looking at similar prices to just starting with a 200 amp.
The labor for a 200 amp service vs a 100 amp is almost exactly the same. a 200 amp service ends up being a little bit more expensive because the panel, the meter socket and the wire is more money. The wire needed is the service drop(down the side of the house(or from the pole on an underground service) and the 5 or six feet from the socket to the panel.
I’ve kinda assumed you are replacing the socket and drop but if you are not it would be much cheaper to remain with a 100 amp service. But that does leave you with the headache of not enough slots.
I’d always recommend a 200 amp.
Wonder through Lowes. Their competitors are more likely have somebody come to help when you just want to nib. You will find plenty of NM-B without ground wires and 2 prong outlets. DIY beware. As I mentioned before, you can see the difference between 100 and 200 amp boxes. Yes, everything from the pole or vault to the box must support the amperage. Most places the electric company will be happy to upgrade you to 200 amps. Even 400 if you are thinking of an electric tankless water heater. If your electric company limits you, you can still put in the 200 amp box you eventually may need, but with a smaller main breaker.
I still have the same old wire, box, and 100 amp main as when my house was built in 1970. Some time the electric company put in a 200 amp meter. I don’t know if it is new meter socket, but it is still the old housing. The only thing I can see that is new is the meter itself.
2 wire nonmetallic cable and 2 wire receptacles are still available to repair existing 2 wire installations. it is legal and required to use that in most of the USA.
a DIY needs to shop carefully. you don’t want to use 3 wire material on a 2 wire system. you don’t want to use 2 wire material on a 3 wire system.
12/2 is 2 wire ungrounded. 12/2 G or 12/2 w/G is with a grounding conductor.
All meter bases have been CL200 for quite a few years now. That doesn’t mean that they all support 200A service they way they’re installed, though. But the meter base should not be a cost difference in 100A vs. 200A unless you already have a smaller meter base and your jurisdiction and utility will let you re-use it in a project of this scale. If it is a modern(ish) base and not something like an A-base, you’re going to get a CL200 meter the next time they do scheduled meter replacement anyway. I’ve watched the utility do this in CL100 bases lots of times.
Your utility may or may not upgrade their part of the project (wire on poles / transformers / drop to your house). Around here, they won’t do it unless the billing shows that you’re using close to the rated capacity of the existing stuff. As an example, I had a job which replaced 2 100A panels in a 2-family with 2 200A panels. The utility refused to ugrade the drop from the pole. In an 40-unit apartment house job I looked at but declined to bid on, the service feeders were actually hot to the touch.
I guess I shouldn’t complain too much - in New York City ConEd would run jumpers out of manholes across sidewalks when the service feeder failed. I’ve also seen them run cables from streetlights (2, to get 240V) aerially to a residence because they didn’t want to replace the underground facility. That one lasted for 5+ years.
If you need the panel space (number of breakers), a 200A panel may actually wind up being less expensive. Let me explain - certain popular panels are heavily discounted at places like Lowe’s and Home Depot - the QO 200A 40-position panel was $192 at both for a number of years. At the same time, the QOM2100VH 100A main breaker needed to downgrade that panel for 100A service was $250 and not carried by either store. $250 buys a good amount of service entrance cable upgrade.
I’m a bit worried about your ungrounded 3-prong receptacles - somebody took a shortcut (badly, as you also mentioned they’re all hot/neutral reversed) and they probably did other stuff incorrectly as well, which you’ll need to hunt down and fix.
Read this, memorize it, then print it and carry it in your wallet. 
If you ever have any thoughts of remodeling the kitchen, expect to need more new circuits than you ever dreamed of.
When I was living in Contra Costa County, the requirements (and I don’t recall if they were imposed by the state or by the county) were such that running a 100-amp sub-panel to the kitchen was not such a nutty idea. In 2006, they were calling for dedicated lines to feed the dishwasher, disposer, built-in microwave, each refrigeration unit (eg: one for a regular fridge and one for an under-counter wine cooler) two or more countertop receptacle circuits, plus one for an island, and the lighting had to be on a different circuit (and must be CFL or other non-incandescent format.) All told, for a 15x12 foot space, we’d have been required to up the wiring to nine dedicated lines plus the 240 line for the oven. Other add-ons like trash compactors, instant hot water taps, etc. also would need their own circuits.
Oh, and bathrooms are also now either required or highly recommended to each be on their own dedicated 20-amp line to feed today’s high-power hair dryers, curling irons, etc. When my sister remodeled her master bathroom, I had her run two dedicated 20-amp lines - one to each of the “his and hers” sinks. Overkill? No - she no longer trips breakers when doing her hair.
As they say, the more info you have, the easier it is to make a wise decision.
You all have been most generous with your knowledge and I am grateful.
We’ve decided thus: upgrade the panel to 200 Amp and plenty of bays. Do what we need to do now for immediate safety and functionality. Put off until the kitchen remodel what we can (lines to machines we don’t have yet.) and take advantage of the electrician’s offer of a no-interest loan.
I’ll be getting a book on electric repairs. Safety is paramount and it’s time to quit blowing fuses when I try to make coffee and toast at the same time.
Thanks again to all of you learned peoples for your time, effort and wisdom.
Ignorance has lost another battle!
Just curious. Can I tell from the outside what my meter base is? As I mentioned, my house was built in 1970 and except for the meter is original as far as the main breaker. Maybe within the last 10 years, the electric company installed a newer 200 amp meter. It is a CL200, GE type 1-70-S.
I think several people have made some good points. You need slots, slots, slots. The cheapest way to get them may be a popular model 200 amp box. You can buy breakers that put 2 circuits in one slot, but a 20 slot box may only be rated for 20 circuits.
If it hasn’t been painted over, there may be useful markings stamped on it somewhere. It might be easier to look at your service cable if it is not in conduit and see what size conductors it claims to contain. If those aren’t rated for 200A, whether the meter base is or isn’t won’t matter. Everything up to the top of the service head is your problem and subject to electrical code. Past that, the utility handles it and doesn’t have to abide by code. I’ve seen many cases of scrawny utility drops feeding beefy service entrance cables.
Most state regulatory commisions require periodic replacement of utility meters. That seems to rely on self-reporting by the utilities, though. If a meter base is an obsolete style or in an inconvenient location, it might get ignored. The worst case I’ve observed is a gas meter installed in 1970 still in service in 2005. Note that this is the install date - the actual meter may be much older, as the meter shop rebuilds them if possible. The abolutely worst meter replacement experience for most homeowners is the water meter. Many older homes don’t have street shutoffs, and the street-side valve at the meter is usually corroded. Around here, the water utility shuts it off as far as they can, changes the meter, turns the valve back on, and if it still leaks the homeowner gets told to “call a plumber”.
I once worked for a wire and cable company. I have seen the specs for the covering of SE cable. I am leary of messing around with my 40 year old drop. The original markings are long gone. My eyes are out of calibration, but the neutral/ground can’t be more than #4 aluminum.
Well, I was hoping it was old enough that the sizing info would be embossed and not printed. You’re right - any print would have degraded.
Remember that the neutral is only going to carry a maximum of half of the service rating, and potentially (pardon the pun) a lot less - if there is equal draw on both legs, the neutral current is essentially zero. I say “essentially” because there’s a minor consideration if you are fed from 2 legs of a 3-phase service (as all residences in my neighborhood are).
The neutral could carry the difference between the 2 legs. Or 100 amps if I could somehow have 100 amps on one leg and none on the other. However most of the amps should go to ground on my ground rod connected to neutral and ground busses in my box. In my box, an old GE, they are one stamping.
I may wait for an outage and take a good look at my service. The meter to main has some much thicker copper wire.
I’m just wondering if an increase in the number of electric cars and their charging stations will make lots of people want to expand their home electrical capacity.
I saw in Consumer Reports that the Tesla wants a 70 Amp circuit (90 Amps gives a full recharge in 4 hours). Not that everyone’s going to buy a Tesla, but perhaps someday…
For recharging a car at night, many existing systems should be able to handle the load by adding an existing box dedicated for that purpose. You can usually get a second meter to get a lower rate for off hour usage. But if you can afford a Tesla, you can probably handle the cost of an upgrade to the electrical service.