120v Single Leg???

[kwired]

In rural Texas I have seen overhead lines on utility poles with only one wire; they are connected to single transformers at residences.

One word: SWER

Single Wire Earth Return

Not my cup of tea, I'll stick with 2 wire

That is 4 words, 1 acronym

Is also on the medium voltage side of the transformer, good luck trying to operate many things at 120 volts using earth as a circuit conductor.

 

[mbrooke]

That is 4 words, 1 acronym

Is also on the medium voltage side of the transformer, good luck trying to operate many things at 120 volts using earth as a circuit conductor.

:roll: Engrish is not and has never been my major :thumbsup:

 

[meternerd]

I'm surprised you'd even be able to find a utility that would offer a 120V 2W service, let alone 200A. The old services that are 120V 2W are only 100A. As far as I know, there is no Kwh meter built to meter 120V 2W (Form 1S meter) rated at 200A. 120V 3W from a 120/208 service (Form 12S meter), maybe, but that would still involve two "phases" and a neutral.

 

[jumper]

I'm surprised you'd even be able to find a utility that would offer a 120V 2W service, let alone 200A. The old services that are 120V 2W are only 100A. As far as I know, there is no Kwh meter built to meter 120V 2W (Form 1S meter) rated at 200A. 120V 3W from a 120/208 service (Form 12S meter), maybe, but that would still involve two "phases" and a neutral.

IDK, page 4.

https://www.nipsco.com/docs/default-source/builders-developers-docs/er19270.pdf

 

[meternerd]

IDK, page 4.

https://www.nipsco.com/docs/default-source/builders-developers-docs/er19270.pdf

Hmmmm...interesting. Never heard of Nipsco. Learn something every day. I know none of the utilities I've worked for would ever offer that kind of service and I have no idea why anybody would want one. If you have a single phase primary, you still would use a single phase 120/240 3W transformer and meter. Weird.

 

[K8MHZ]

FWIW traffic light cabinets and street lights are often fed from a single 120 volt source.

I think some lighted signs are, too.

 

[mbrooke]

I think some lighted signs are, too.

Your thinking would be correct.

 

[jumper]

Hmmmm...interesting. Never heard of Nipsco. Learn something every day. I know none of the utilities I've worked for would ever offer that kind of service and I have no idea why anybody would want one. If you have a single phase primary, you still would use a single phase 120/240 3W transformer and meter. Weird.

Beyond weird.

 

[GoldDigger]

In rural Texas I have seen overhead lines on utility poles with only one wire; they are connected to single transformers at residences.

Using earth return at MV you can run a single actual overhead wire to a transformer, but that single phase transformer can just as easily supply a 240V service through use of a center tap as a single ended 120V service.

 

[mivey]

That's strong words from someone who doesn't understand the circumstances... you can skip over my threads if you have nothing good to offer.

I agree Jraef may have jumped too soon. Don't sweat it, maybe he was experiencing technical difficulties. He's generally a good guy.

 

[Jraef]

I agree Jraef may have jumped too soon. Don't sweat it, maybe he was experiencing technical difficulties. He's generally a good guy.

Jumped too soon? Yes, for sure, and for that I apologize.

Generally a good guy? Meh... not this week. My daughter is getting married on Saturday, I'm a wreck right now and everyone around me is paying the price. :rant:

As to the subject matter, there is still something amiss here.

Basically the only difference on my end is im not hooking anything up to the center tap of the pig, and I even have a 120v meter!

The 120V service drops I have seen on old houses STILL used the same connections from the TRANSFORMER to the meter, the only difference is that there is no second hot lead coming off of the transformer, or in some cases the transformer is still connected with 3 wires, but one hot wire stops at the meter. That Nipsco diagram shows this 2nd option, as does the one in this document. No matter what, the grounded center tap of the transformer secondary is STILL where the Neutral of the 120V is derived and connected. Could it be a custom transformer specially made for a 120V service where it is just one winding on the secondary with one side grounded? Sure, I suppose so, but in my experience Utilities don't like "specials", they like to use the same limited number of devices that they carry in inventory and make adaptations for special case customers.

 

[K8MHZ]

Jumped too soon? Yes, for sure, and for that I apologize.



As to the subject matter, there is still something amiss here.

The 120V service drops I have seen on old houses STILL used the same connections from the TRANSFORMER to the meter, the only difference is that there is no second hot lead coming off of the transformer, or in some cases the transformer is still connected with 3 wires, but one hot wire stops at the meter. That Nipsco diagram shows this 2nd option, as does the one in this document. No matter what, the grounded center tap of the transformer secondary is STILL where the Neutral of the 120V is derived and connected. Could it be a custom transformer specially made for a 120V service where it is just one winding on the secondary with one side grounded? Sure, I suppose so, but in my experience Utilities don't like "specials", they like to use the same limited number of devices that they carry in inventory and make adaptations for special case customers.

The same here, twice in my life. Both times there was 120/240 triplex from the transformer to the weatherhead with one leg just cut and folded over. Only the neutral and one hot went to the meter. Those were originally installed around 1910-1920, but had up to date meters on them.

 

[kwired]

Jumped too soon? Yes, for sure, and for that I apologize.

Generally a good guy? Meh... not this week. My daughter is getting married on Saturday, I'm a wreck right now and everyone around me is paying the price. :rant:

As to the subject matter, there is still something amiss here.

The 120V service drops I have seen on old houses STILL used the same connections from the TRANSFORMER to the meter, the only difference is that there is no second hot lead coming off of the transformer, or in some cases the transformer is still connected with 3 wires, but one hot wire stops at the meter. That Nipsco diagram shows this 2nd option, as does the one in this document. No matter what, the grounded center tap of the transformer secondary is STILL where the Neutral of the 120V is derived and connected. Could it be a custom transformer specially made for a 120V service where it is just one winding on the secondary with one side grounded? Sure, I suppose so, but in my experience Utilities don't like "specials", they like to use the same limited number of devices that they carry in inventory and make adaptations for special case customers.

But at same time there is nothing too out of the ordinary about having a transformer with a 120 secondary, unless that POCO never supplies any 208/120 services derived from three single phase transformers.

 

[Jraef]

But at same time there is nothing too out of the ordinary about having a transformer with a 120 secondary, unless that POCO never supplies any 208/120 services derived from three single phase transformers.

D'oh!
:slaphead:

 

[mivey]

Jumped too soon? Yes, for sure, and for that I apologize.

Generally a good guy? Meh... not this week. My daughter is getting married on Saturday, I'm a wreck right now and everyone around me is paying the price. :rant:

As to the subject matter, there is still something amiss here.

The 120V service drops I have seen on old houses STILL used the same connections from the TRANSFORMER to the meter, the only difference is that there is no second hot lead coming off of the transformer, or in some cases the transformer is still connected with 3 wires, but one hot wire stops at the meter. That Nipsco diagram shows this 2nd option, as does the one in this document. No matter what, the grounded center tap of the transformer secondary is STILL where the Neutral of the 120V is derived and connected. Could it be a custom transformer specially made for a 120V service where it is just one winding on the secondary with one side grounded? Sure, I suppose so, but in my experience Utilities don't like "specials", they like to use the same limited number of devices that they carry in inventory and make adaptations for special case customers.

X1-X2 is the standard used and would leave the outside X3 bushing unused. I figured the OP just mis-spoke and I did not consider it important.

FWIW, It is not likely that it would be connected X1-X3 because of the ground strap to tank under X2 and you would get 240 volts X1-X3 when checking before leaving the shop.

At any rate, as a field tech, the OP probably would not have to re-jumper as most utilities have the shop persons do that before it leaves the yard. Since OP probably does not move the internal jumpers routinely, he probably overlooked how it would actually be, especially if it is a configuration that is not used a lot.

The something amiss is not a main focal point IMO but still worth correcting for the record.

 

[growler]

For the life of me, I can't figure out why this brand new home I'm building a service for calls for a 200a 120v service.

If you ever do figure out why they want this type of service be sure to post the reason.

Maybe they are apostate Amish and wish to move onto the grid one leg at a time.

 

[truck41trouble]

Ok, so after a beat down for questioning the engineering dept, And a handshake from my super for questioning the engineering dept here is the verdict.
Apparently the builder and electrician reviewed this with the new construction division, whom then issued an order to energize after inspection. At the time there was a summer intern working there ( last summer) who reviewed the application and submitted it to the line division.
We don't offer a 120v service of any kind, not for anything. Every new installation is required by us to have 240v brought to the meter and the end use is required to be balanced between 2 legs when pratical. The builder and " electrician" figured since there were no 240v loads that they could just drop one leg and save 280' of conductor, which the intern engineer never caught. There was even a 120v 200a meter specd out for the installation along with the meter pan.
The idea was for me to parallel the secondary windings of the pig, bypass the center tap and ground one side of the secondary, giving 120v at the full rating of the xfmer.
I do a lot of new services, I probably build a new 3 phase bank at least twice a week and do most of the residential services in my coverage area, I have never connected or saw a transforner connected this way. But that connection was indicated on the slip.
We don't have yardmen anymore, if you need a pig, your loading it up yourself weather your a troubleman, lineman, or substation tech.
Long story short, they are pulling the 3rd conductor and ill go back and hot it up on Friday.

Thanks for all the help and trying to clarify. I thought it was also interesting to get different points of view on the subject.

Oh and Jraef, congrats to your daughter man.



Sent from my VS987 using Tapatalk

 

[mbrooke]

Ok, so after a beat down for questioning the engineering dept, And a handshake from my super for questioning the engineering dept here is the verdict.
Apparently the builder and electrician reviewed this with the new construction division, whom then issued an order to energize after inspection. At the time there was a summer intern working there ( last summer) who reviewed the application and submitted it to the line division.
We don't offer a 120v service of any kind, not for anything. Every new installation is required by us to have 240v brought to the meter and the end use is required to be balanced between 2 legs when pratical. The builder and " electrician" figured since there were no 240v loads that they could just drop one leg and save 280' of conductor, which the intern engineer never caught. There was even a 120v 200a meter specd out for the installation along with the meter pan.
The idea was for me to parallel the secondary windings of the pig, bypass the center tap and ground one side of the secondary, giving 120v at the full rating of the xfmer.
I do a lot of new services, I probably build a new 3 phase bank at least twice a week and do most of the residential services in my coverage area, I have never connected or saw a transforner connected this way. But that connection was indicated on the slip.
We don't have yardmen anymore, if you need a pig, your loading it up yourself weather your a troubleman, lineman, or substation tech.
Long story short, they are pulling the 3rd conductor and ill go back and hot it up on Friday.

Thanks for all the help and trying to clarify. I thought it was also interesting to get different points of view on the subject.

Oh and Jraef, congrats to your daughter man.



Sent from my VS987 using Tapatalk

Wait, this was permitted and the guys work was actually approved? :blink: I can't see that... I mean if an "electrician" can concoct something like this, I can only imagine what else is taking place with his work.

But in terms of saving on conductor you actually end up using more. 120 volt load balanced across two 120 volt legs produce less voltage drop and less amperage then all loads across a single 120 volt leg. 200amp service could literally go down to 100amps no questions asked.

 

[JFletcher]

Ok, so after a beat down for questioning the engineering dept, And a handshake from my super for questioning the engineering dept here is the verdict.
Apparently the builder and electrician reviewed this with the new construction division, whom then issued an order to energize after inspection. At the time there was a summer intern working there ( last summer) who reviewed the application and submitted it to the line division.
We don't offer a 120v service of any kind, not for anything. Every new installation is required by us to have 240v brought to the meter and the end use is required to be balanced between 2 legs when pratical. The builder and " electrician" figured since there were no 240v loads that they could just drop one leg and save 280' of conductor, which the intern engineer never caught. There was even a 120v 200a meter specd out for the installation along with the meter pan.
The idea was for me to parallel the secondary windings of the pig, bypass the center tap and ground one side of the secondary, giving 120v at the full rating of the xfmer.
I do a lot of new services, I probably build a new 3 phase bank at least twice a week and do most of the residential services in my coverage area, I have never connected or saw a transforner connected this way. But that connection was indicated on the slip.
We don't have yardmen anymore, if you need a pig, your loading it up yourself weather your a troubleman, lineman, or substation tech.
Long story short, they are pulling the 3rd conductor and ill go back and hot it up on Friday.

Thanks for all the help and trying to clarify. I thought it was also interesting to get different points of view on the subject.

Oh and Jraef, congrats to your daughter man.
Sent from my VS987 using Tapatalk

Glad when my instinct is right:

I would at least pitch to the customer running triplex now instead of later; any future buyer will want/require a 240V service, and the wire cost is probably the same.

 

[mivey]

The idea was for me to parallel the secondary windings of the pig, bypass the center tap and ground one side of the secondary, giving 120v at the full rating of the xfmer.
I do a lot of new services, I probably build a new 3 phase bank at least twice a week and do most of the residential services in my coverage area, I have never connected or saw a transforner connected this way. But that connection was indicated on the slip

You could make jumpers for a X1-X3 120 volt configuration (with center X2 unconnected) and it would work just fine:

with A <-120-> B and C <-120v-> D you get

C*A tied to X3 and B*D tied to X1 yielding

X3 <-120v-> X1 with a paralleled winding between them.



Standard (NEMA I believe) is X1-X2 with outside X3 unconnected:

C*A tied to X2 and B*D tied to X1 yielding

X2 <-120v-> X1 with a paralleled winding between them.



4 external bushings has the outside bushings at 120 volt but since the bushings are aligned X1 then X3 then X2 then X4 (D B C A) you still get X1-X2 because X1 ties to X3 and X2 ties to X4 (D*B and C*A) and you get them paralleled like:

X4 <-120v-> X3
X2 <-120v-> X1


Maybe some youngster was confusing the two because the bushing arrangements are different.