Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


PG&E question.

PG&E question.

PG&E question.

Got a guy needing bigger service. He has 200A 1p and PG&E told him, "No problem, we can give you 3p 208 or 240 200/400/or600A service, your choice".
The county said "Na-uh, no 600A but 400A is fine".

He requested 400A 3p 240V service and everything was moving forward until today.

Today a different PG&E engineer calls him and states, "If you want 3p you need to get an easement across the county road and we'll have to trench the county road, dig up your neighbor's yard for 30 feet then tear up your driveway. But if we stick with 1p we can just up-the-drop coming to your place and you can use a rotary phase converter."

This sort of feels like a brush-off play but maybe there's some rational reason for the radical difference between 1p and 3p upgrades. Anyone got any logic for this?

Keith Cress
kcress - http://www.flaminsystems.com

RE: PG&E question.

Is the existing service overhead or underground?
Does PG&E have to replace an existing underground feeder?
Has PG&E stopped using quadruplex Neutral Supported Cable for service drops?
PG&E may have had some issues with heavier three phase service drops and stopped using the heavier Neutral Supported Cables.

"Why not the best?"
Jimmy Carter

RE: PG&E question.

If the customer sticks with single phase, PG&E might not be planning to change the service drop at all for a conversion from 200 Amps to 400 Amps. From the utility standpoint, they only need to have facilities in place that can handle the actual load (they don't have to match the rating of the customer's equipment).

Utilities that I've worked for will typically install 350 MCM aluminum service conductor for a new 400 Amp service, but they almost never replace existing service conductor (usually 4/0 Aluminum) when a customer upgrades an existing 200 Amp service to 400 Amps.


RE: PG&E question.

Sounds more like a "grandfathered" situation. His existing service is already there and they can replace it as needed, so they can "replace" it with larger conductors (if necessary, as RobertNC stated). But for a totally new service, as in 3 phase, it has to meet new easement codes etc. that may have changed over the years.

I ran into that once when I rented a big old (1890s) building that had an Open Delta 240V 3 phase service with one transformer center tapped for a split phase 120/240V drop. I was trying to sub-let parts of the building and the split phase thing was inadequate, so I asked for an upgrade to a 480Y277V service drop, then I would do my own single phase transformers and tenant sub metering. The PoCo wanted to charge me an arm and a leg for that 3rd 12kV wire, even though it was right there on the same pole where my Open Delta transformers were mounted. They could increase the size of my open delta transformers to give me more power, no charge, but to give me a whole new service drop required bringing the entire system up to the newer codes, and I had to pay for that.

"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

RE: PG&E question.

I don't work for PG&E, but our field engineers, are not actually engineers, they are more of estimate people. They report to the distribution planning engineers, who review their work.

It might be that the field people did not see a problem, but the reviewer did.

PG&E might be required to put all new services underground in your area, and that might be the reason for the project stop.

RE: PG&E question.

GoogleMaps Street View of this discussion

It's the house on the right with the Camper-shelled Truck.

Things to note:
It has it's own pole in the driveway to keep the wires above trucks.
The place is the only load (besides the streetlight) fed by the transformer.
The existing transformer is about the size of two big coffee cans.

Bill I don't think it's a distribution issue as they're happy to imbalance what they've got over an opportunity to balance a load.

Robert that's an interesting bit of info: Double the current don't bother changing the wire..

Thanks for all the considered thoughts! I'm betting cranky's last sentence is the show-stopper. I wish the engineer would just say that if it's the case. Or rationally ignore it and do the right thing. Clearly tearing up the county road and the neighbor's yard and driveway and the guy's property to put one single place on a miles long road underground serves no one including the county. Sigh.

Keith Cress
kcress - http://www.flaminsystems.com

RE: PG&E question.

It's also possible that the local government that controls the franchise rights has decreed that all new services shall be underground. The initial answer may have been to a generalized question about service options while the second had to do with that specific location. Just guesses, but there's probably more to the story.

If it is a franchise issue, there could well be a specific permit for that crossing that includes the number and size of conductors. Violating the franchise conditions would not further the career of whoever designs the new service.

RE: PG&E question.

Perhaps they are also changing to a pad mount transformer? The pole looks a bit tight to accommodate two more transformers.

RE: PG&E question.

It didn't seem like there's any place to put a pad mount on the pole side of the street.

And true-dat David.

After what Robert said about not bothering to upgrade the wires I'm starting to see that the game may be that PG&E can "upgrade their hardware" without changing a single thing going to the user making it not even a customer upgrade, avoiding all forms of permits from their side of it.

I directed the guy to ask "why" so I expect an answer sooner or later. I'll get back with it so we can all add it to our encyclopedias.

Keith Cress
kcress - http://www.flaminsystems.com

RE: PG&E question.

Google Earth's 'look back in time' feature shows that an addition was recently built on to the back of the house. From the utility side, I would assume that the upgrade to a 400 Amp service is to allow for the installation of a second panel to feed circuits in the new addition.

If the house is all-electric, the main drivers of its peak load will be heating/cooling and hot water heating. Throw in some lighting and appliances, and the service has probably never seen more than 20 KW of actual load (which is only about 80 Amps). If the customer is adding three phase equipment that is small enough to run off of a phase converter, I wouldn't expect it to add significantly to peak demand.

The existing transformer is probably rated for 25 KVA continuous and most utilities are willing to accept short term loading to about 140% of the transformer rating (more like 160% in the winter).

Without documentation of additional electrical equipment that is being added (like grow lights for an indoor agricultural operation), the utility might install a 400 Amp meter in the new meterbase but they will not likely change anything else.

RE: PG&E question.

Hi Robert.
He's added two machines. A machining center with a 30HP spindle and a lathe with a 20HP motor. PG&E has done an onsite inspection with what Cranky108 suggests is an 'estimator'. When he came he asked to see inside and when he did he burst out laughing. He said, 'Everyone expected it to be a grow." Once he saw it was actually a machine shop he was greatly relieved, took a picture and said, "We can provide whatever you need. What do you want?"

That was followed by the aforementioned downer call.

His current 200A service is entirely unable to adequately support just the single machining center. The voltage at the house side of the rotary phase converter dips from 240 to about 180V just starting the 5hp coolant pump which trips off the control system on 'voltage error', I presume from the coffee-can transformer impedance.

Keith Cress
kcress - http://www.flaminsystems.com

RE: PG&E question.

I've dealt with PG&E once and it was enough. We were supposed to provide data that a VFD installation would meet IEEE519. But, they were designing a system with capacitor banks to correct the inductance of the line and they were just bright enough to design the system so the resonance point of 4 capacitor banks landed between the 4th and 8th harmonic. When they realized this, they decreed that the customer equipment can't produce any harmonics because they couldn't possibly do anything extra to protect their banks unless they spent about 2 years studying the situation before they could approve it.

RE: PG&E question.

Yeah Lionel, that's why we call it Pacific Graft and Extortion. They are charging this guy fifteen hundred bucks to tell him no/yes/no/yes/no and that 'It will cost you $8k, $60k, not sure k' and 'it will take 6 to 15 months', 'if we do it'.

Keith Cress
kcress - http://www.flaminsystems.com

RE: PG&E question.

In this climate where everybody is so sew happy, and the federal, state, and local governments are breathing down the utility necks, some of this is understandable (but not all of it).

It's true that so many calls for service upgrades are for grows, but then again, so many don't give any notice. If they don't burn down the house, or blowup the transformer, we are not allowed to inform the police.

How often is he going to use the machine shop? It is possible to power the equipment from a generator.

The strange thing is in parts of the US there are people who believe they are not to be worldly, and use propane powered generators for there business.

RE: PG&E question.

Hi Cranky; We are in an "Air Quality Board District" that will fine you into oblivion for running a generator regularly and this is a full-on machine shop with more than $200K in new machines that need to pay for themselves.

Keith Cress
kcress - http://www.flaminsystems.com

RE: PG&E question.

It appears to me that that existing tx is tapped onto a 4 kV line and a puny one at that. That could be some of the reason for the dip with the coolant pump or whatever. Kind of a rotten looking pole too with two electrical circuits on alley arms and numerous comm lines.

Look at the pole behind the POV of the link given, it appears they are replacing it at the time of photo with a new pole to support the new tx which is tapped off the higher up 12 kV line.

Of course this is probably like talking to the wall, but wouldn't it be cool if you could find some actual engineer in the company to talk to to save money by installing a second tx for an open delta service on that pole, and bringing a quadplex down to the pole where the customer's tx is now and then following the existing service drop. This way no easements are changed, extra hardware is minimized and everybody wins.

RE: PG&E question.

Hi John; What you propose is exactly what we're hoping for. Today I was called by my client who told me that he got called by the PG&E engineer and between the two of them my client got a bit annoyed and the engineer got 'defensive' and my client realizes he's essentially clue-less about all this.

End result: I was asked to call the engineer and we will meet at the site and go over the 'issues'. I'm going to hope he agrees to your last paragraph but I won't be holding my breath. I thought there was no underground on that street but studying the above gooogle spot and your comment about the 'new pole' shows "underground" and all the new houses across the street are not visibly supplied power.

Next to the new pole a guy is on the ground in the bushes. Not sure what he's doing but that may be the underground service to all those houses.

Keith Cress
kcress - http://www.flaminsystems.com

RE: PG&E question.

A side note with regard to the above comment about reusing the same service drop for a heavier service:

I have seen occasional installations where PG&E installed a fourth insulated wire suspended in parallel with an existing triplex to convert to three phase.

Probably never happen any more, but you could always ask...maybe there is one guy left who understands cost/benefit ratio.

RE: PG&E question.

Both trucks wear AT&T badges. The workers present are working on communications, not electric service.

RE: PG&E question.

I met with the PGE guy today... Interesting meeting.

I got a very serious feeling they wanted nothing to do with upgrading the service from what felt like a strictly Debbie-downer kind of vibe. The guy actually looked like he was sucking a lemon when he showed up. He had a look on his face like he'd just received tragic news. Never smiled once and his entire argument was - bottom line, 'we can't hang 400A 3-phase wire across a two lane road between two power poles 48 feet apart'. Don't they hang secondary 400A size-ish wire between poles down every street in the country to service several homes per transformer?

Does this make sense to any of you guys?

If 400A was needed then it had to go down the pole across the county road (only perpendicularly) to a box in the ground and underground to the shop. ~$80k.

He did seem maybe/possibly/noncommittally/vaguely willing to check out the possibility of replacing the triplex with quadplex and supplying 200A 3Φ 240V. Probably open delta..

Keith Cress
kcress - http://www.flaminsystems.com

RE: PG&E question.

It may be best to get an attorney involved and have him check the applicable laws to see if an underground service is really required.

Being PG&E and all that close online friends have told me about them I would not be surprised if the people you are talking to are clueless. Between communications, staffing and employee competence they have a lot to work on.

If this was around here they would set a new pole on the property, extend the 3 phase over from the road, new bank and drop no hassle. IMHO whats holding them back is getting 3 large pots on the already busy pole.

RE: PG&E question.

Two things, PGE is not the same as PG&E, and the people I know at both companies are very good at what they do.

That said, I am also sure both companies, as well as mine have a few people who are lacking in some ways. And it's because good people are hard to find.

Many zoning regulations also pertain to undergrounding of electric lines. Check it out.

RE: PG&E question.

I'll agree with cranky, in this case the ampersand is important if you want to get the right company. They're the ampersand company, mine isn't.

The sucking lemons approach isn't useful, but there may be a variety of issues you aren't seeing. What the utility can do in the public right-of-way is governed by the governmental entity responsible for that right-of-way; what they can do in one city may not have any bearing on what can be done in a different city. You can even find that what can be done along a city street is different from what can be done along a county road that passes through the city, can be different from what can be done along a state highway in the same city.

If their largest TX is 4/0 and they're prohibited from (or just don't do) double TX road crossings there's no way to get there. Maybe a primary road crossing, but that might require new poles on both sides of the road to have the clearances for a primary tap.

The perpendicular crossing requirement for the underground option isn't a surprise at all, almost certainly a requirement of the road owner. Diagonal crossings just cause trouble down the road (no pun intended) and many cities don't allow them.

RE: PG&E question.

Which is why someone who can make sense of it all needs getting involved. If PG&E can't give straight answers, you need someone who will. And yes I am well aware this is about Pacific Gas And Electric.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close