Fifth jaw for meters

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winnie said:
That approach would have essentially the same error as the regular single phase approach. The meter is calculating usage with the assumption that the two legs of the service are equal.

If you have a large imbalanced current but the service is 'stiff' with no voltage drop, then the result is accurate. But if the heavily loaded leg drops to say 110V and the lightly loaded leg rises to 130V, you are still being charged as if each leg were at 120V.

-Jon
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Again would depend on details, if you have line to line volt reference of 240 to the meter but a .50 multiplier somehow built in or a transformation to give 120 to the meter then yes it would be seeing it as if each leg were at 120. If you directly tapped one ungrounded and the neutral for supplying the meter voltage reference then it would see either the 110 or the 130 depending which leg it was tapped from. But I do see your point in how this still can have errors.
 
Does anyone have a comment on my question post number 12 about the difference between those two meter sockets, the 114 TB (with 5th jaw accessory added) and the 115 TB? The 115 is a factory five jaw and it says it's for three phase three wire. Now I get they will be using the two watt-hour method for that and they need the fifth terminal to get voltage from the third phase, but this seems mechanically equivalent to the metering of 120/208 single phase where you need a voltage reference on that grounded conductor. So in either case you have that conductor splicing in the meter socket with a pigtail up to the 5th jaw......So why do they spec two different meter sockets for the two?
 
Coppersmith said:
My GC is in a hurry. I can order several different units at Home Depot, but it will take a week. I found a useable unit at a local supplier. They have to ship it in from a warehouse overnight. (I don't have an account so I'm paying too much.) It's listed in the POCO guide as a 4/5 jaw. I hoping this means the fifth jaw is removable. The link below from Greybar lists it as a five jaw.

https://www.graybar.com/meter-main/p/97136111
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Some utilities will provide the meter base for free if it’s being installed on their system, others may charge for it, but you may check with them.
 
Dominion Power provides meter bases. I can usually walk in and grab 100a or 200a residential bases and walk out.

I have never seen a meter base for sale at the orange or blue stores here.
 
electrofelon said:
Does anyone have a comment on my question post number 12 about the difference between those two meter sockets, the 114 TB (with 5th jaw accessory added) and the 115 TB? The 115 is a factory five jaw and it says it's for three phase three wire. Now I get they will be using the two watt-hour method for that and they need the fifth terminal to get voltage from the third phase, but this seems mechanically equivalent to the metering of 120/208 single phase where you need a voltage reference on that grounded conductor. So in either case you have that conductor splicing in the meter socket with a pigtail up to the 5th jaw......So why do they spec two different meter sockets for the two?
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Take a look at the internals on the 115TB. It has three “line” and three “load” terminals.
The 114TB only has two for single phase and you add the fifth clip and tie the jumper to neutral.1415440D-F03C-459A-9A75-6B487F4F3D77.jpeg357AECFA-D270-4685-ACCA-435CEE124160.jpeg
 
Hv&Lv said:
Take a look at the internals on the 115TB. It has three “line” and three “load” terminals.
The 114TB only has two for single phase and you add the fifth clip and tie the jumper to neutral.View attachment 2556396View attachment 2556398
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Trying to find this in a Milbank catalog, must be something sold to a particular region or something. Noticed they have several different "regional" catalogs. Some POCO must specify this design for some reason. Five jaw version possibly used on grounded phase systems?
 
Coppersmith said:
My GC is in a hurry. I can order several different units at Home Depot, but it will take a week. I found a useable unit at a local supplier. They have to ship it in from a warehouse overnight. (I don't have an account so I'm paying too much.) It's listed in the POCO guide as a 4/5 jaw. I hoping this means the fifth jaw is removable. The link below from Greybar lists it as a five jaw.

https://www.graybar.com/meter-main/p/97136111
Click to expand...
Followup: So the supplier finally got my meter main and I took possession two days later than promised. (When paying a premium to get material, you would think they would have their act together and get you the material when promised.)

When I opened the box I discovered it to be a four jaw meter socket. There might be a fifth jaw kit for this, but I didn't see any mention on the box or included documents. Four jaws is all I want so worked out for me. It's now nicely installed.
 
Coppersmith said:
Followup: So the supplier finally got my meter main and I took possession two days later than promised. (When paying a premium to get material, you would think they would have their act together and get you the material when promised.)

When I opened the box I discovered it to be a four jaw meter socket. There might be a fifth jaw kit for this, but I didn't see any mention on the box or included documents. Four jaws is all I want so worked out for me. It's now nicely installed.
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You been on a vacation for the past year.

Two days is not late anymore. :poop:

Three months isn't a long lead time anymore either.
 
kwired said:
Trying to find this in a Milbank catalog, must be something sold to a particular region or something. Noticed they have several different "regional" catalogs. Some POCO must specify this design for some reason. Five jaw version possibly used on grounded phase systems?
Click to expand...

See post 16
 
Sparkey1981 said:
Make sure to ask the POCO if it needs to be in the 3oclock position or 9 oclock position
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Most "network" meters used for 120/208 single phase metering have a removable fifth stab that can be installed at 9 oclock or 6 oclock (looking at the meter socket). Most common is 9 oclock.
 
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