Shop from hell moves on

Scott,

I have just gotten thru doing exactly what you are asking about. Only difference is my outside main breaker was 40 years old and rated 40amps. Yes

40 AMPS!!!

I had already put a new panel in garage and redid the one in house as well. I wanted to replace the main panel with meter but after getting some info and checking with city it became clear that I didn't need to do this. For one thing it would have required redoing the entire house which included ripping lots and lots of holes in wall in order to bring the existing wire to code. This woul dhave been cost prohibitive and as it turns out not needed. I instead put in a larger main breaker into existing main panel. Remember you will never have all your equipment on at same time. Just calculate a over exagerated scenerio.

ie: washer and dryer on, TV on in each room, air compressor running, AC on and you running that 50hp lathe :)

Chances are you will need much less then you thought. This is legitimately how you figure out your current needs. Ofcourse you always add some room.

As far as aluminum wire, you will be pleased to find out that aluminum wire is the norm for utility companies. Cheaper and lighter then copper. The bad name for aluminum came out when people had it in their homes and used the wrong receptacles and switches with them. Aluminum is fine as long as is hooked up correctly and used with proper components.

Home depot has one of the best electrical books I have seen. It is called Wiring simplified. Has everything you need for code compliant circuits and only costs 5.95. Is usually hung up in thier electrical section, not in thier book esction. This book is recommended by many for its no bull type of info.

To be honest I don't see you needing to have the meter replaced, but keep in mind the less you involve the electrical compnay and city the better it normally it is for you cost wise and hassle wise.

just some thoughts from someone who just went thru all this.

Oliver

house has a main panel outside,

subpanel is rated 125 amps, the

that is the absolute minimum

add on, from the main panel.

of it, create a new subpanel

right next to the main outside

breaker in the main

have an electrical

on that today.

know how folks here

do you think ? Rip it

I forgot to mention that I did run new line from main to house to carry the extra load. Everything was done to code and I over estimated everything by at least 50% in worst case scenerio. Just wanted to make sure you knew I took no shortcuts :)

"V8TR4" one thing it would have required redoing the entire house which included

I made the mistake of calling PG&E today, they basically told me, you have what you have, and we want $1200 just to talk to you about any improvements.

So you didn't upgrade the meter. Is the meter 40 amps ? Ie., are you still within the overall limit you started with ?

In my main panel at present, there is the 100 amp breaker that feeds the old

100amp panel, plus a 30 amp breaker someone added (legal or not) to run the pool pump panel in the back. PG&E won't tell me (unless I pay them) what my limit is, they just say "add up your current breakers to find the total for the meter" (which, by the way is complete bulls**t, since you and I both know the total breaker numbers are allowed to exceed the panel rating).

So if I replace the 30 amp pool breaker with (say) a 100 amp breaker to the new subpanel, they'll ok that based on the "you are allowed to exceed" idea.

This seems to me to be ideal, because it leaves the old panel completely alone, gives the full 100 amp capacity to the shop if so required.

The key things seem to me to be if (A) the inspector will have a fit seeing the two 100 amp breakers, and (B) if the meter does something reasonable if you exceed the 100 amp rating the meter may or may not have (don't know, since they won't tell me).

I am guessing this is correct, since the meter side has a nice locked door under it with a "tampering illegal" warning. Ie., the power company protected themselves, and the main breaker box is your problem.

I'm going to also continue this back in a separate thread. ("electric meter from hell", hey, I like Mat Gronieg, sue me).

Did you have to use the "oxidation paste" on the terminals after disconnecting and reconnecting them ?

Yea, I got that one. Its good, but it does not really get into specifics about subpanels (under "updating old construction").

Yes, very true.

This was about twenty years ago, so things might have changed....

.........But.........

I pulled the meter, did the work and then called them to let em know someone had broken the seal. A couple months later I noticed there was a new seal on the meter.

I'm puzzled. Why are you putting a floor substructure up there? It doesn't look like there's enough headroom above your new floor to be very useful.

I'm not quite sure why you want to close that space in anyway. The collar ties look like they were doing their job, and it doesn't look like you're going to gain much usable space. So why are you going to all that trouble merely to reduce the headroom in your shop?

Gary

Almost certainly you have a Type 2S meter. Those come in 60, 100, 200, and 320 amp sizes. We can rule out a 60 amp meter since it was originally installed in a 100 amp service. Now they are all 7 inches in diameter, but they are different depths (not including socket). If it is 5.5 inches deep, it is a 100 amp meter. If it is 4.75 inches deep, it is a 200 amp meter. And if it is 3.625 inches deep it is a 320 amp meter.

Of course, since the meter *base* is included in your 100 amp panel, it is almost certainly a 100 amp base. In other words, it doesn't matter how much more than 100 amps the meter can carry if it is mounted in a 100 amp base, the sizing of the conductors in the base and panel limit you to a total load of 100 amps. So you already know the answer before you look.

Gary

SNIP "......................Now they are all 7 inches in diameter, but

Hey Gary,

That's interesting. Counter-intuitive though. Why is that?

Take care.

Brian Lawson, Bothwell, Ontario.

The heavier meters don't need the extra space for more iron core and wire turns in order to operate. Put another way, they're lower impedance meters because necessarily a heavier load is also lower impedance.

The "motor" that, with the gears and dials, is the analog computer in the meter is an eddy current disk that rotates in a field provided by a coil in series with the load, and another coil that's in shunt with the load. The shunt coil has many turns, the series coil has few. They are arranged to produce a quadrature field. That makes the disk spin.

(And it only spins when voltage across and current through the meter are *in phase*, hence it only measures true power, not VARs.)

Note, there is also a permanent magnet eddy brake in the meters to give the "motor" a known load. That's the same for all meters in a series and can be ignored for the purposes of this discussion. But it is essential to the meter's operation.

Ok, the disk and gears are the same in all meters of a given series. The only thing that changes for different amp rated meters is the size of the core and the amount of wire wound on it to produce the quadrature magnetic fields.

The strength of an electromagnet is a function of ampere-turns. In other words, the more amps, the fewer turns you need, and vice versa. So the core and coils for a high current meter can be smaller than the core and coils for a low current meter while delivering the same torque. Hence the housing of a higher current meter can be shallower than that of a lower current meter.

Gary

I don't think so. The 200 amp meters seem just as accurate at low currents as the 100 amp meters. (60 amp meters were only made for installations that were 120 volts only.) In fact, the power company will usually just install a 200 amp meter regardless of the actual panel size (unless it is larger than 200 amps of course).

That way they only have to stock one model meter. I've never seen a *new* meter that was smaller than 200 amps. I think that the deeper meters are simply a holdover from the days when household panels were much lower current.

AFAIK all the disks are the same size. Different meters will have a different Kh factor, though. That's marked on the meter face.

Gary

Some new updates got added to my shop building page:

The structural inspection happens tomorrow, leaving piping and electrical to go.

Scott -

Suggest you put in 25 amp sockets - that is the ones with the T on one lug. Normal plugs plug into them just the same, but the contacts are larger.

Naturally - consider what code pushes first!

Martin

Just a minor nit-pick. Those are 20 amp sockets.

As long as you've got 12 guage wiring and 20 amp breakers the code folks should be happy with

20 amp sockets.

Bill Ranck Blacksburg, Va.