Inadequate Incoming Service Conductors

I have 400A Service (two 200A Meters and Panels, 208/120 Single Phase) at my building, which should be adequate to power the machinery (via phase converter) that I plan on adding. The incoming PG&E splice box was not locked, so I opened it to verify the incoming line, and was shocked when I found this:



#2 AWG ALCAN, which is good for about 90A, being split to feed (2) 200A Meters! The wire past the split is 3/0 THN, which is about right for 200A.

Here is the PG&E guideline for commercial service entries. See Table 2.

https://www.pge.com/includes/docs/pdfs/mybusiness/customerservice/startstop/newconstruction/greenbook/servicerequirements/063928.pdf

The conduit coming is per the PGE Guideline...at 4", but my incoming conductors are bout 6 sizes too small..even for 200A...let alone 400.

Finally, here is a schematic of the current system, with wire sizes labeled:

Dropbox - Existing SVC.pdf

I am surprised we have not already melted these. What approach should I take to get PGE to correct this, and what is the ballpark cost, given that the conduit currently installed is the correct size. All they would have to do is have the incoming leads pulled and replaced with the proper size. There is a buried vault at the corner of the property, and I hope there is a junction in there with larger feeder cables. The distance from our building to there is only about 60 feet.

Upgrading A Service Lateral

To get an upgrade, first thing you will need is a load schedule for your equipment and building loads. Your utility should have a form, with the way they want it listed.
Without that they may not want to talk about it. You must prove the need for the upgrade and how much upgrade you actually need. It's all based on the connected load and not the panel size.

It may need a transformer upgrade as well as the conductors. Without knowing the actual load it's hard to size the equipment for adequacy. They wont install more than you need, there's no economic incentive for that, unless you want to pony up for the oversize.

In the spec provided here's why the conductors are sized less than the service size. They were adequate to feed the load that was there, before you arrived. And it looks like a good long while, based on the oxidation on the alu lugs.

B.
Install the number and size of conductors, as shown in Table 2 on Page 3,
to meet the individual initial demand load.
Take load characteristics and growth into consideration.
C.
It is permissible to install a smaller transformer and fewer conductors to serve a
long term initial load with the intent of installing a larger transformer and additional conductors should future load increase occur.

Click to expand...

The utility does not use the wiring size ampacitys that the NEC code uses, they have their own tables for overhead and underground services. They also may use different wire insulation ratings than listed in the code.

Come up with a load schedule first then contact your service planner, to find out what is required to meet the load. Only they can tell you what the cost will be. Looks like from the spec that they provide the cable and installation to the service terminal point.

SAF said:

To get an upgrade, first thing you will need is a load schedule for your equipment and building loads. Your utility should have a form, with the way they want it listed.
Without that they may not want to talk about it. You must prove the need for the upgrade and how much upgrade you actually need. It's all based on the connected load and not the panel size.

It may need a transformer upgrade as well as the conductors. Without knowing the actual load it's hard to size the equipment for adequacy. They wont install more than you need, there's no economic incentive for that, unless you want to pony up for the oversize.

In the spec provided here's why the conductors are sized less than the service size. They were adequate to feed the load that was there, before you arrived. And it looks like a good long while, based on the oxidation on the alu lugs.



The utility does not use the wiring size ampacitys that the NEC code uses, they have their own tables for overhead and underground services. They also may use different wire insulation ratings than listed in the code.

Come up with a load schedule first then contact your service planner, to find out what is required to meet the load. Only they can tell you what the cost will be. Looks like from the spec that they provide the cable and installation to the service terminal point.

Click to expand...

]]

Thanks for the input.

Well this could REALLY suck. I spoke with a PGE Engineer last year when I was considering having 3Ph put it. That was cost prohibitive, because the PGE Std for 3Ph 400A service is to use 5" Conduit. The incoming is 4" The transformer is 150' away, across the street. It was going to be $30K+.... for the following:
*Digging up the street
*New conduit
*Backfilling and repairing the asphalt
*Curb work
*Concrete pad for free standing meter and gear
*New meters, lots of rewiring

So I decided to just use a phase converter. I mentioned this to PG&E, and they said I could not do that...they do no allow phase converters..which seems like BS. Load is load...why can they tell us what we can not use? I later spoke to the tech staff at Phase Perfect, and they explained that PG&E probably had issues with static or rotary phase converters which can create problems for the utility. They probably have no idea what a PWM phase converter is... So I planned to just say no more, and go ahead an use the converter.

I mistakenly assumed that with 400 service, I could just power up. All the wiring on our side is adequate, but this incoming wiring size issue is a disaster. If I give PG&E a load schedule that shows them I want to use a phase converter, they are going to say no, and I will have that whole battle to fight. Crap...I can not afford to dump $30K more into this deal for 3 Phase.

Maybe I need to buy a few more clapped out 220V arc welders, set up some welding tables, and tell them I am going to have a fab shop...and need to run 180A.

What about telling them we want the building to be viable as a industrial rental, and we must have more amperage capacity to make the building marketable? There is a building across the street where they put in 3phase...and it is for rent.

Shooter7 said:

.... There is a buried vault at the corner of the property, and I hope there is a junction in there with larger feeder cables. The distance from our building to there is only about 60 feet.

Click to expand...

Seems odd that the utility doesn't have to meet the NEC. A 200A main protecting #6 AL wire is clearly a nono. Perhaps your inquiry could be limited to that.

You OK with checking out the vault? That would be my approach. While the utility would officially frown on it, I would regard it as proactive.

Nice that PGE will bear the cost of installing new equipment.

Neil

See 12 . C

"It is permissible to install a smaller transformer and conductors........"

Prolly ain't got enough transformer either.

You are going to have to show enough demand for them to upgrade.

Smoke the line fuse and they will get the point.

Fill out the load schedule with the equipment listed as a 1Φ load equivalent. Add another piece of equipment to compensate for the RPC portion of the load.

Use HP ratings or 3Φ FLA x 1.732 for 1Φ equivalent.

Sometimes a better strategy is to use what you have to the limit. Once you have some history of the higher billable usage, meaning they are making some money from the service. Then when you run out of capacity and are causing problems on the transformer, wiring, or the neighborhood distribution system, then they become a lot more amenable to doing an upgrade. Your then proving the need.

Many utilities have a limitation on the maximum motor size that's connectable to a 1Φ service. That's why they prohibit RPC's, allows loads larger than the 1Φ motor limit.

For your own benefit you should do the load schedule to see what your actual requirement is. There is a demand factor for diversity of loads. You may not need as big as a service as you think, when factoring in the load diversity. List what you have on paper and put some numbers to it, include the building loads.

Take a look for their "Green Book" that will give you a lot more details on their rules than the spec sheet you listed earlier.

Another strategy could be to install a smaller than 400A 3Φ service in the conduit you have, if it would meet your requirements. You can run quite a bit of equipment on a 225A 3Φ service.

SAF Ω

To give you an example of you may not need as much as you think you do.

A shop I redid for a tool shop customer had a 400A 3Φ 208V service in the building before he moved in. We ran a load schedule for the customers equipment to be installed. The load schedule numbers added up to about 600A requirement with the load diversity factored in. We wanted to install a 1200A panelboard, But the pole transformers were rated for 400A.

The service planner allowed us to use the existing transformers for the anticipated load. We upgraded the service bus riser and panelboard to 1200A, fed from the 400A transformer bank supply. The customers large CNC and additional loads ran without a hitch.

A year later the customer calls and wants to add a 100HP spindle bridge mill??
We hooked it up to the existing transformers and it also runs without a hitch. If it didn't then we could justify calling for a increase on the transformer bank. But in reality it wasn't required, not yet anyways. And this summer was one of the hottest on record here, sailed right through even with the extra AC load.

SAF Ω

Thanks for the all input.... I can't quote all your posts, so I will respond by post number...

#4: Already started to. I cleaned it off today, but I did not have a narrow enough hook to grab the lifting studs... Then I decided it was not such a good idea...

#5: The transformer is feeding 6-8 buildings...at least two have 3 phase. The transformer is not dedicated to just my building. The transformer enclosure is pretty large....about 5'x'5x4' tall. Here is a pic (Dropbox - Transformer.PNG) The system is 208 Wye (208 phase to phase, 120V phase to ground). I also thought about trying to deliberately smoke the lines. Turn everything possible on in the building... run two arc welders...start the water heater after leaving it off for 3 days. Turn on AC...every light...a couple space heaters...and a leaking air compressor. I think I could get to about 250A. I doubt that would be enough to smoke #2 AWG Alcan (normally rated for 90 A at 75 DegC)

#6/#7: Is the reason the utility limits motor loads on single phase because of inrush, which is easily 3-4 times FLA? I see how this can upset phase balancing in a system where you have 3 Ph Wye, with different buildings using different phase pairings. But with a small VMC, most of the loads are not really motor loads. They are run off PWM inverters, so no inrush. Will I have any luck trying to convince the PoCo that a 28.5 kVa load on a machining center is not the same as a motor load? I am thinking a better approach is to just find a way to get the incoming line upgraded, and not tell them about the VMC. I know that I will not be running it at the limit, and the loads are not motor loads with inrush. It will just look like load to the system....

If I tally up everything I possibly can on a load schedule...NOT including the VMC, I will have the following:
*5 HP Mill or 5 HP Lathe. Assume these are small enough to run off a phase converter. The equiv 208V single phase load will be about 25 FLA
*Med sized stick welder: 208 1Ph, 75A
*Small stick welder: 208 1Ph, 50A
*Med Wire Feed Welder: 208, 1 Ph, 50A
*5 Hp Air Compressor, 220V 1 PH, 28 A
*4500W Water Heater: 220V 1 PH, 25 A
*(3) 110V Drill Presses: 120V, 1Ph, 10A
*Normal office loads, lighting, etc, 20A
Total = 283 A.

Now, in reality, no way the all run at once. What will they actually believe on a load calc? Can I claim I will be using 2,3 welders at once in the future. What I would like to have done is the following:

*Get the incoming service line upgraded to at least 2/0. I would feel comfortable with that.
*Get rid of the two 200A meters, and have (1) 400A meter. Why? This will make it easier for me to wire up the big phase perfect.

How does anyone ever invest to start a business if they will not put in the power till you have usage...but you can not have usage, till you have the power to run your machines. F***!

Are you urban enough to have a fire department? (Location is rather vague) Ask for a fire inspection. Or ask your insurance company for an inspection. I can't believe your electric entrance is so far below what the NEC regards as safe.

And be sure to get cost information for on-site temporary generator service while your shore power is red-tagged until it's fixed... Unless you can afford to be closed for that duration.

Or, buy the building next door that's for rent, and has 3-phase, and sell yours. At least moving will be easy.

Chip

Have you considered powering each of your 3 phase machines with VFD's?
5 hp is right at the top end for single phase feeds last time I looked but things change so quickly with electronics. I would suggest consulting with a local industrial drive shop to see if they can meet your requirements. Cam

I'll just chime in on the conductor size issue. Yes, Utilities do not have to follow the NEC, they OWN the equipment and connections up to and including the meter, they can do what they want, risk what they want. The NEC is "overly" conservative for a host of very valid and historical reasons, but the utilities can and do push things to the max.

I once had a 500kVA pad mount transformer feeding a pump station at which we had to increase the pump sizes, requiring 750kVA. The utility crew came out and changed the fuses and nameplate on the transformer...

I think the only real danger to the OP's equipment is from low voltage... and there should be a specification in the power company's service contract that they have to meet. My advice, put the equipment in, run it, monitor the line voltage while you're running max load, and if the voltage doesn't drop, you're golden. If you burn up the powco's equipment, that's their problem. You won't get any satisfaction until you do, so don't worry about it.

Dennis

Most of your load is welders, running these guys at full load continuous often?
Know the duty cycle of these machines before you melt down your welder?
If it is working why complain? If you are buying lots of power the provider will generally be happy to give you a bigger pipe into the building.
Grow your shop and ante up into the world of $3,000-6,000 monthly electric bills They get nicer when you are sending them money.
When I went from only 200A 440 3 phase to 800amps they fell all over themselves to dig up the road and other things for free as they really wanted those monthly checks.
Your power company may be different but mine likes to "follow the money".

Not sure given your loads that you could "melt" this system down. A goodly temp rise yes, a melt and short, not seeing it.
Have you burned down a electric system inside or out? It is not as easy at it seems. (BTDT)
Bob

jraef wrote: "Yes, Utilities do not have to follow the NEC, they OWN the equipment and connections up to and including the meter, they can do what they want, risk what they want."

Umm... I hear what you're saying, but I OWN the equipment and connections from the meter up to and including my machines -- why can't I do what I want, and risk what I want? (Assuming one-man shop, no dependents, and nothing flammable within two miles.)

Just because they would prefer not to spend the money, and live on the edge, doesn't make it right. If their stuff blows up, you might have damages to cars (and people) out in the parking lot, and the electric customer would risk equipment damage and have lost income from being down for however long it takes to repair. Yeah, you can get some insurance money, but that doesn't get that promised rush job for your biggest client completed on time.

Just sayin'.

Chip

For a one man shop and the loads you listed could most likely run that off of a 100A main without a problem. Every one of the loads you listed is intermittent except for the lighting.

That would leave you the 2nd panel to connect your CNC to and have a dedicated main. Because the panel is likely limited to a 100A breaker, replace it with a disconnect dedicated to the PC and CNC load.

Once you jump to a 400A service you can no longer use thru the meter services, you jump up to a CT (current transformer) cabinet and transformer driven meter. Meaning you will need to replace the entire service as well as the utility costs.

Don't go there, until it's really necessary. Listen to Carbide Bob, that's the way it works in reality.

One last point. I would be cautious about complaining and asking for an inspection, as some mentioned. The normal service rules require that there be only one service per occupancy, and you have two existing. Many inspectors would require that you remove one to comply with the rule. Then you would be left with half of your existing capacity. Or be forced to do the entire utility upgrade and service entrance costs.

Run what ya brung, till it no longer works. Then you will get a better reception from the service planner.

SAF Ω

Shooter7 said:
So I decided to just use a phase converter. I mentioned this to PG&E, and they said I could not do that...they do no allow phase converters..which seems like BS. Load is load...why can they tell us what we can not use? I later spoke to the tech staff at Phase Perfect, and they explained that PG&E probably had issues with static or rotary phase converters which can create problems for the utility. They probably have no idea what a PWM phase converter is... So I planned to just say no more, and go ahead an use the converter.

Click to expand...

I see you are in Northern California but in a different locale from me. We have SMUD (Sacramento Municipal Utility District) and our high voltage is 240 VAC, rather than 208 as you mentioned.

I couldn't imagine paying for 3 phase since it would be $20-30K even to talk about it. I also don't know what SMUD thinks about phase converters since I would never, ever talk to them about such a thing.

If you call an inspector in to have your installation checked, I'd bet a dollar to a donut that they will tell you that it's all wrong and you have to fix it at your expense. That's what inspectors do - the ones I've seen are there to cause confusion. Example, the last one that came out was an uninvited fire inspector because he noticed that my weeds were too high. He asked me what the address was for my second house in back of the house. I said that it's not a house, it's a barn. He said, it's got to be a separate house because it's got an air conditioner. WTF? I told him the same address as my house and he left. ( I cut the weeds the next day).

The above suggestion about VFD's is a good one. I use a phase converter since I'm only running one 3 hp, 3 phase mill motor. Like I said, I never asked anyone. LOL.

Modelman has it right. The actual issue is voltage drop on the VMC. All the other loads I listed were ways to justify getting the conductors upgraded.

I have found an easier solution. The problem with going 3 phase is PGEs super conservative conduit sizing. They are cheap on conductor sizing, but they want huge conduit so pulls are easy to make. They insist on (1) 5" buried conduit for 3Ph 400A, which I was thinking I wanted. 3PH 400A is a LOT of juice. I do not need even close to that...but I DO need the 3Ph. The solution is to upgrade to 3PH, but DOWNGRADE the rating to 200A. If I go to 3 Phase, 200A, I think this will give me all I need, and the 3PH 200A PGE conduit requirement is only 3". I have 4". So I will be able to get new wires pulled, with no earthwork.

Worst case, I need 28.5 KVA for the VMC, 5 HP for a manual tool like my Mori Lathe or a saw, and 5 HP for a Air Compressor...AT THE SAME TIME. Part running on the VMC...I start up the lathe, and the Air Comp is running...plus some building loads. Of course, the VMC will not really ever be running at the max 28.5...more like 17-20 max... So a realistic total is 35 KVA....or 100A. This leaves 100A for other building loads (Pull off 2 of the 3 phases to wire into the existing single phase system)

I think I can make this work. So downgrading to 200A, but 3 Phase will allow me to use the existing conduit, and not have to trench up the street..which is where all the cost was coming from.

So here is my plan:
1. Run some tests, loading everything up, and measure voltages. Extrapolate that data, and see if I can estimate what the voltage drop will be when running the VMC on a Phase Perfect, without ever changing the incoming service lines. If the drop will be more than 4%, I will have to get the conductors upsized. Once I open the can or worms with PGE, I have to go 3Ph because they will likely never allow me to run a 26.5 KVA VMC off a converter!
2. If I have to call PGE, the plan will be to put 3 phase in, but downgrade the rating to 200A, and replace my two single phase 200A meters with one 3Ph unit. This will avoid the meter problems noted above. Have PGE make a 3 Ph hook up to the transformer and pull new wires.

Is there any chance that PGE will conclude that 200A is NOT ENOUGH for a VMC that is nameplated at 26.5 KVA?

That's more than enough even as single phase.

Modelman said:

I think the only real danger to the OP's equipment is from low voltage... and there should be a specification in the power company's service contract that they have to meet. My advice, put the equipment in, run it, monitor the line voltage while you're running max load, and if the voltage doesn't drop, you're golden. If you burn up the powco's equipment, that's their problem. You won't get any satisfaction until you do, so don't worry about it.

Dennis

Click to expand...

I agree. Your actual loads will likely never come on all at once and that is why NEC allows derating of conductor sizes. Wire sizes listed in NEC tables are based on heating of the conductors, voltage drop,, and insulation types. Your service conductors are more than adequate for your usage unless as previously stated you experience voltage drops that could be damaging your equipment.