Situation: (Residential 120/240v)

Service Entrance cable and Meterpan must be replaced and relocated. It is 100A with a 100A MB panelboard inside. Customer would like to upgrade to 200 but doesn't have the $$ to do the whole job right now.

Question:
The SE cable and meterpan will be replaced with 2/0 and 200A Meterpan now and will continue to feed the 100A MB panelboard until that will be upgraded to 200A. Are there any concerns with doing this? Increased fault current levels?
(Service is overhead with #4 triplex Alum drop from pole)

Bill

[This message has been edited by Bill Addiss (edited 07-30-2001).]

Great question, Bill!

At first I thought that it would be a code violation, but upon further thought, I can't see how it would be. It is protected at 100amp, an amount not greater than the rating of the se conductors, so it seems to be ok.

Fault current is a concern, I would think. Let me sleep on that one.

Another thought, I would think the utility would frown on this type of set up for the following reasons. Their meter, rated for 200 amps, costs more than the 100 amp meter in place now, as well as the cost for the service man to come out to reconnect. Doing this work for only a 100amp service means that their payback period will be greater, since the load will be less than 100amps, so it will take longer for them to recoup their costs. If this was for a true 200amp service, one could assume the load would be above 100amps, thereby their intake of money would be greater, reducing their payback period. Dollars do run the industry, after all.

Just a thought.

Rick

Rick,

In my area We can only use 1 type of Meterpan for 0 to 200A. It is rated at 200A OH and UG with a bypass. They use the same meter, We just plug it back in. There is no reconnect for them either if We use the connectors that they supply. Sometimes they will come out and change the drop though.

Bill

U do come up with some good ones Bill !

I would thing it's ok, and a request probably more common than we let on.

What about the opposite?
A old 60A service gets a new 100A panel, but the main gets changed to a 60A ?

If you are talking about increased fault levels due to the larger SE cable, I would think that it would be negligible. Even if it did increase slightly, isn't most residential service equipment rated for typical residential distribution transformer fault currents?
BTW Bill,
I've often wondered about res. meter ratings. Most of the meters around here have the designation, "CL200" on them. But, I was told long ago that this has nothing to do with the rating. Hard to believe though, because every one I know just plugs in the same meter (socket type) after an upgrade to 200A.

[This message has been edited by Redsy (edited 07-31-2001).]

Sparky,

Yes, it does seem to come up now and then where something has to be done with part of the Service right away. It makes sense to replace with a larger cable outside here because we have to install a 200A Meterpan anyway. Replacing with 100A cable now and changing it again later on seems like a big wasted expense.

Your example (unless very temporary) would make me uncomfortable, even though maybe legit.

Redsy,

I really don't know about the meters. I suspect that if a different one is needed it only gets put in after the customer has shown an increased demand. Many times they don't even change the drop unless it's very old.

Bill

What is the big hooplah all about?

Wouldn't the fault current capable of being delivered only be as much as the #4 service drop from the pole? Increasing the size of the SE conductors would not make the fault current available more or less.

A Q for you Bill, is 2/0 rated for 200A service? You could not get by with nothing but 3/0cu. here in Houston.

Our meters here are of but one type also. They are all CL200(class200). And yes that is rated for 200A service. Older installations when most services were 100A used a CL100. All are the same now for socket type meters. The CL100 meter gets changed to a CL200 if the customer upgrades their service, but very seldom as you stated Bill does the #4 drop get replaced with 1/0 unless the drop is old or there is evidence that the cust may be adding load(adding on a room or two, pool)otherwise the #4 drop that has served so well for 20 years is still capable of handling the cust needs.

Meter ratings are as follows;

CL100- 100Amps and 60A services
CL200- 100AMps to 200A services
both are socket type meters

CL400- 400A service which is a bolt-in type meter.

And just one more Q Bill,
The utility allows the electrician to make the permanent conn. at the WH? Even if they supply you with the connectors. You would have a band of furious lineman on your hands if you tried that down here
Down here the electrician at his discretion will make temp conn so the cust will have power until the utility makes perm conn.

I think the available fault current would be determined by TOTAL impedance of the ckt, which would be different, however slightly, for #2 al. vs. 4/0 al. tapped onto the #4 svc. drop.
In Phila., area the electrician makes permanent taps. The utility does not provide connectors. This confusion has resulted in some electricians installing romex connectors for "temporary taps, until the utility replaces them".

BTW glenn35,
Regarding the so-called "trans-socket" meter pans used these days for residential 400 amp svcs. I thought they used a 200 amp plug-in meter, and if needed they could be outfitted with CTs and connected to a transformer-rated meter. How recently have 400 amp line-current meters been used?




[This message has been edited by Redsy (edited 07-31-2001).]

Bill, I've been doing that for years. Since both serving utilities require a minimum 2" rigid for a risor if it is the attachment point for their triplex, I run 3/0cu and use a 200A MB. The utility stopped supplying meterbases a few years ago. The electrician has to supply them and a 200A costs $21.50 and a 100A runs $16.50-not much more. I lost track a long time ago how many of these 100A upgrades I was called back to re-upgrade. I always tell a customer who wants to limit their upgrade to 100A to save money that the labor charge is the same and the materials costs are less than 20% more for the 200A but you just can't reason with some folks.

>A old 60A service gets a new 100A panel, but the main gets changed to a 60A?

I have no problem with that, in fact, I recommend it.

I like to do this, that is, use a 200 A panel to get the spaces and the heavier bus, but put in a 100 A main because of the present service rating. Even if the service remains 100 A, it is served by a bigger panel. I prefer working in a larger panel.

There is a big desire for "separation" in loadcenters nowadays. When you do the calculation for a new home and come up with a need for a 100A or less service, you can bet that when you're actually wiring the house you'll find you need more than 20 poles in your panel. I was glad to see ITE and SqD respond with 30 and 32 pole 100A panels. Normally I'll just jump up to a 200A service and always use a 40 pole panel. But when doing duplex condos you can't always do that. I did put a 40 pole panel with a 100A main in my garage just for the ability to separate, dedicate and isolate. My computed load is less than 60A.

glenn35,

Hey, what's a hooplah anyway?

I'm just collecting info and opinions here. I see no problem with it but it does seem to make people think twice.

Yes, We can use 2/0 Copper for Residential 200A Service. You should be able to also unless there's a local thing against it. See Table 310-15(b)(6)
For other than single phase Resi we need 3/0 Copper too.

Yes, they give us the connectors to make the final connections for up to 200A Resi services. Maybe an effort to bring down what was one of the highest rates in the country (?)

Fred,

Since they went to the bypass type our meterpans cost about $100 with hub. And it is rated for 200A.

Bill

Redsy the 400A meters we use are self contained. Meaning that no other equipment such as CT's or PT's are needed. I have been at this utility for 16 yrs and they have always been around. The meter does not plug into a socket like a standard meter. Instead they bolt onto the metercans terminals.

The city I work in requires 150A min on service. The utility no longer furnishes the meter base, either. I put in almost 200 A exclusively, the panels are cheaper. Also the utility runs a 1/0 Aluminum drop no matter what the meter base is rated at.