No second meter :(

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LakeLeaf

Well-known member
Joined
Jun 7, 2010
Messages
1,424
Location
South Lake Tahoe, California
I've talked through a half dozen people at the power company about getting a second meter installed.

We are supposed to get time-of-use rates here next year, so I was hoping to put the EVSE on it's own meter and only use the cheapest power to fuel it back up.

My utility's time-of-use rates are set up so that if you use any significant amount of power during the day (peak times), they charge you 2x to 3x the rate you would have if you weren't on time-of-use. Of course, the cost at night is pretty cheap as they want to sell you the power at night when they have plenty of it. Unfortunately, I need my computers and networks running 24x7 so will use a lot of power during the day so can't move my whole house to time-of-day.

The power company tells me that a structure (in this case my structure) can't have two meters because the fire department won't know what circuits are on what meter. (Why they just wouldn't kill both, I don't understand). Too bad, as I could have rolled all of the expenses of the second meter into the EVSE install and the tax break and had dirt cheap power to charge with.

Anyone else looked into doing this?
 
Met with SMUD (Sacramento Municipal Utilities District) yesterday.

About 5-6 weeks ago they stopped allowing "dual-meter adapters" for the simple reason that they are not UL listed and apparently ADD to the panel rating. (Meaning ... on a 200A panel ... the run to the house could potentially see 200 + 40.) For liability reasons they obviously can't do this.

A solution, however, would be to de-rate the 200A panel to a 160A panel (but obviously that could cause load problems for the existing devices). This, however, does not solve the mentioned Fire Departments concern of two disconnects. Then again, with proper labelling of BOTH disconnects ... that problem would be solved.

Suggestion: call your fire dept chief; explain; get concurrence. Then talk to the City and Utility again.
 
LakeLeaf said:
Anyone else looked into doing this?
Of course ;)

Figuring out the best course of action when it comes to power, equipment and what is and is not allowed can be tricky. Back when I got my first electric vehicle I had to think about the exact same thing. I investigated putting the EV on its own meter but soon realized for me the cost and hassle of installing a second meter and a whole separate line, even if it is allowed, would take a very long time, if ever, to recover the cost of my investment in reduced power bills. So I ended up putting the whole house on the time of use meter. For me it was the right thing to do and still is. Would I spend less on power if I had two meters? Probably, but even now with a new Leaf on its way and the tiered power rates I figure the most I might save a month having two meters is $30. Still not enough savings for me. I am also hopeful that with the advent of smart meters it will eventually become much cheaper to have two meters at which time I probably will switch.

So have you done some estimating on what your costs for power will be with the different scenarios?
 
You can also see information on TOU metering in the local areas thread, the utilities subthread. In the city of Los Angeles, the Department of Water and Power told me that no dual meters are allowed because of no UL approval issue (this was a concern of the city Dept. of Building and Safety) but a completely separate TOU meter next to existing meter is allowable. I have already done the first step with the DWP person coming to the house to draw a diagram of where they would want the TOU meter to be placed. They want to encourage this, I think, because they want us to charge at night with cheaper rate and when they have electricity excess. Many people are not going to want whole house TOU metering (too expensive) and also there will be people like us who want to account for the EVSE electrical use separately. So in essence, we will have 2 DWP accounts, one for the house and one for the TOU meter.
 
Kataphn said:
Many people are not going to want whole house TOU metering (too expensive) and also there will be people like us who want to account for the EVSE electrical use separately.
Don't automatically assume that whole house time of use metering is too expensive without doing the math first. It really comes down to each individuals offered home power rates, tiers and usage habits.

Air conditioning is probably the biggest factor for most people but it was not for me since I do not have it.
 
LakeLeaf, are these your rates?
http://www.nvenergy.com/brochures_arch/rate_schedules/np_res_rate.pdf
If so I think you have a better deal than I do ;) Wait, no usage tiers? Now I'm jealous!
http://www.pge.com/includes/docs/pdfs/about/rates/rateinfo/rateoptions/res/e-9.pdf
 
LEAFer said:
About 5-6 weeks ago they stopped allowing "dual-meter adapters" for the simple reason that they are not UL listed and apparently ADD to the panel rating. (Meaning ... on a 200A panel ... the run to the house could potentially see 200 + 40.) For liability reasons they obviously can't do this.
That makes no sense - the 2nd meter of the dual meter should not tie into the existing panel at all aside from running a couple wires through the box from the 2nd meter straight to your EVSE.
 
LEAFer said:
Met with SMUD (Sacramento Municipal Utilities District) yesterday. About 5-6 weeks ago they stopped allowing "dual-meter adapters" for the simple reason that they are not UL listed
Well, there is a UL-listed dual meter adapter made by E.J. Brooks Utility. See http://www.brooksutility.com/catalog/product-detail.asp?ID=570 The UL certification can be verified at http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/showpage.html?name=PKAX.E142236 That page only lists one of the model numbers for the adapter, so I'm not clear if the other configurations are also UL listed. I also have no idea on pricing or availability, I have not contacted the company.

LEAFer said:
and apparently ADD to the panel rating. (Meaning ... on a 200A panel ... the run to the house could potentially see 200 + 40.) For liability reasons they obviously can't do this.
Yes, adding a second meter with a new load will increase the load on the wiring before the meters. But all the NEC requires is a load calculation, although I suppose that your utility may impose additional restrictions.

From the NEC point of view, here is how it works: Utility transformer <--> Utility wiring <--> Service conductors <--> 1 or more main disconnects (grouped). You are responsible for the service conductors and size the conductors based on the calculated load on the disconnect(s) served. Each disconnect must be sized greater than its calculated load and less than the service conductor ampacity. But in the case of multiple disconnects, it is allowed to have the sum of the disconnect sizes greater than the service size. E.g. a 100 amp disconnect with a 60 amp load and a 200 amp disconnect with a 130 amp load together on a 200 amp service is OK.

BTW, the NEC load calculation method is very conservative, so there is usually no problem if your calculated load is very close to your service conductor ampacity. The utility usually uses smaller wires, based on their accumulated aggregate experience of actual customer demands.

Cheers, Wayne
 
drees said:
That makes no sense - the 2nd meter of the dual meter should not tie into the existing panel at all aside from running a couple wires through the box from the 2nd meter straight to your EVSE.
Well, the concern would be overloading your service drop; if that requires upgrading, I don't know who pays, you or the utility. I think it varies by utility.

And the wires from the second meter would need to go into a disconnect before going to any utilitization equipment like an EVSE.

Cheers, Wayne
 
drees said:
LEAFer said:
About 5-6 weeks ago they stopped allowing "dual-meter adapters" for the simple reason that they are not UL listed and apparently ADD to the panel rating. (Meaning ... on a 200A panel ... the run to the house could potentially see 200 + 40.) For liability reasons they obviously can't do this.
That makes no sense - the 2nd meter of the dual meter should not tie into the existing panel at all aside from running a couple wires through the box from the 2nd meter straight to your EVSE.
Exactly. That's why the 40A adds to the 200A, causing a potential 240A on the service drop. I'll try and convince someone more knowledgable from SMUD to chime in here. Looks like Wayne has a bunch of good knowledge, though !
 
LEAFer said:
drees said:
LEAFer said:
About 5-6 weeks ago they stopped allowing "dual-meter adapters" for the simple reason that they are not UL listed and apparently ADD to the panel rating. (Meaning ... on a 200A panel ... the run to the house could potentially see 200 + 40.) For liability reasons they obviously can't do this.
That makes no sense - the 2nd meter of the dual meter should not tie into the existing panel at all aside from running a couple wires through the box from the 2nd meter straight to your EVSE.
Exactly. That's why the 40A adds to the 200A, causing a potential 240A on the service drop. I'll try and convince someone more knowledgable from SMUD to chime in here. Looks like Wayne has a bunch of good knowledge, though !

I have heard of utilities that put the second meter in series with the first one and then subtract the second meter reading from the first when charging for the nonEV consumption. Obviously a bit more complicated, and of course I can't find where I saw it before, but it was probably on the PG&E site since that is my utility. Could also be Lakeland Power from when I lived there.


edit: here it is... http://www.cpuc.ca.gov/NR/rdonlyres/4B8FE1E8-6DB1-47BD-BC5D-01CB9A872017/0/PGEAcceleratingtheInstallationofHomeChargingEquipment.pdf
 
1. SDG&E seems to allow the dual-meter adapter, so those "reasons" might not be absolute.

2. If you have "two accounts", does EACH ONE get its own "base" allowance?

3. If you can show a UL adapter to those areas that use "UL" as their "reason", that might get you a "variance" to use the UL-listed unit.
 
palmermd said:
I have heard of utilities that put the second meter in series with the first one and then subtract the second meter reading from the first when charging for the nonEV consumption.
edit: here it is... http://www.cpuc.ca.gov/NR/rdonlyres/4B8FE1E8-6DB1-47BD-BC5D-01CB9A872017/0/PGEAcceleratingtheInstallationofHomeChargingEquipment.pdf
Thanks palmermd! I was looking for that before and I was not able to find it. Does anyone know if these options are available to PG&E customers yet?
 
Spies said:
LakeLeaf, are these your rates?
http://www.nvenergy.com/brochures_arch/rate_schedules/np_res_rate.pdf
If so I think you have a better deal than I do ;) Wait, no usage tiers? Now I'm jealous!
http://www.pge.com/includes/docs/pdfs/about/rates/rateinfo/rateoptions/res/e-9.pdf

Hey Spies -

Not sure those are my exact rates - those look like the NV rates and across the stateline we have a different rate plan.

But, yes, the power is cheaper here then there.

My best guess is that I use 1000kWh peak and 1000kWh off-peak a month. We don't have time-of-use rates in place yet - supposed to start here next year if approved by PUC. I guess I'll have to look a lot more closely to what I can push to the evening and see if TOU will make any sense. It will take a bit more work then I had hoped.

With a second meter, I'd use it for both my Leaf and to run the furnaces from it as they run mostly at night. No A/C here in the mountains.
 
Ah, how I know your pain!

But it looks like at least in Virginia we'll be getting a special EV TOU rate after all! Woo hoo! Just as well I have to wait for my LEAF as the TOU won't go into effect until the State Corporation Commission approves it but it'd be nice to have a smart meter with the EV on a separate, $0.03 rate. Though, by my current calculations, this rate can't beat my current $0.07033 / $0.04187 summer / winter rate.
 
I'm a LADWP customer and that killed the deal for me as the coast of adding a second meter would stretch the payback out to a point where it made no sense economically. A whole house TOU meter is not an option for me due to business equipment which has to be up 24/7. The Blink EVSE has the capability to send the usage information to the LADWP directly eliminating the requirement for a second meter but, of course, they are not equipped to handle this though that are "looking in to it..."


Kataphn said:
In the city of Los Angeles, the Department of Water and Power told me that no dual meters are allowed because of no UL approval issue (this was a concern of the city Dept. of Building and Safety) but a completely separate TOU meter next to existing meter is allowable.
 
Apparently the "Dual Meter Adapter" device (adapts one meter ring to provide two meter rings) is not UL listed.

But, two meters, each installed on a normal meter base, are OK in many areas, but still not permitted in some areas (for fear of using single-family structures as two-family units, I suspect).
 
Yep, LADWP allows that for water (to separate the house from irrigation) but not for electricity. Go figure.


LEAFer said:
I have heard of utilities that put the second meter in series with the first one and then subtract the second meter reading from the first when charging for the nonEV consumption.
 
I'm in the SDG&E service territory and on the ECOtality project. I chose the option of a second meter with the EVSE connected on one of the experimental TOU rates they assigned. The house meter stays on the Domestic Rate with the usage tiers. It was a pretty smooth installation process.

ECOtality applied for and paid for the permit, they submitted the design with the load calcs, and installed everything except for the new second meter. They sent out two electricians to install a new double breaker in my main panel fror the 2nd meter and EVSE run, an inside conduit run above my side door and over to where the second meter base was installed (on the outside of the house with a feed through), an exterior disconnect for the EVSE, and then back inside for another conduit run to the EVSE.

When done, they arranged for the inspection and even waited for the inspector. Once complete, SDG&E was notified and they came out and set the 2nd meter. It was a relatively painless process, and not a dime out of my pocket. Hard to beat that.

My first bill should come in a few days. Other than powering the EVSE all the time, all of my charging was done from midnight to 5am during the super off-peak period. I'll post those results in Jimmy's thread when I get the bill.

RedRandy
 
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