Ever wonder why ???

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goldstar

goldstar

Senior Member
Location
New Jersey
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Electrical Contractor
Ever wonder why POCO's can do things like this :

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And we have to size wire for services in accordance with the size of the main breaker installed and then de-rate and down-size wiring in accordance with 310.16 when we install sub-panels ?

And yes, they're feeding 6 services of various amperages (all 120/208 3 phase but probably not larger than 100 amps each) off the same feeder and transformers:

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I don't know what size the feeder quad-plex is but it seems small by the standards we have to comply with. It's been working a long, long time so I guess it's sized correctly by POCO standards
 
We size by what the NEC predicts the load to be per Article 220.

The power company sizes by what they know the load will be.

They have a much better idea of what the true load will be.
 
Some things to consider.

What is the actual average load?

How long does peak load last?

What size is the transformer supplying it? What size dry type indoor located transformer would you use to supply same load(s)?

The service drop is in free air and not in a raceway or covered cable.

If the drop or transformer does get too hot from overload - it is not located inside a building where it could start the building on fire.

POCO is betting on all this information to save operations costs that would be spent on larger conductors and transformers.

Sometimes there is excessive voltage drop because of undersized equipment from POCO.
 
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brian john said:
Other than looking like a bowl of spaghetti what is the issue?
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No issue really. I just find it peculiar that the POCO can just go ahead and crimp a bunch of wires together and are not subject to a 3rd party inspection and approval.
kwired said:
If the drop or transformer does get too hot from overload - it is not located inside a building where it could start the building on fire.
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Granted, but I've seen service drops and transformers burn up and the POCO just re-installs the same size drop and xfmr.
iwire said:
We size by what the NEC predicts the load to be per Article 220.

The power company sizes by what they know the load will be.

They have a much better idea of what the true load will be.
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Good point. I guess that's the part that bugs me. We have to size and de-rate in accordance with what the NEC predicts while the POCO can run lamp cord from the pole to a customer if they wish.(Just being facetious :p )
 
I think another thing to keep in mind is that if the power company actually had to design their entire system to NEC standards our electric rates would be a lot higher to pay for it.

You would also have thousands of oversize / underloaded transformers wasting additional power. Fault current levels in dwelling units would likely increase meaning more expensive service equipment.
 
goldstar said:
We have to size and de-rate in accordance with what the NEC predicts while the POCO can run lamp cord from the pole to a customer if they wish.
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You don't think it might also have a little bit to do with their conductors being in 'open air' versus ours being crammed into a little box covered by insulation?
 
iwire said:
We size by what the NEC predicts the load to be per Article 220.

The power company sizes by what they know the load will be.

They have a much better idea of what the true load will be.
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I'm sure that's true.
But it just doesn't excuse the the horribly untidy state of the wiring in my opinion.
Butt connectors are bad enough but just having them hanging it mid air - ghastly.
 
Open air and ease of change. A #2 alum is good for 150 amps continuous. a 4/0 is good for 315 amps.
I have wired up houses myself and had to use 4/0 SE cable, only to come back and install #2 overhead after I received my inspection.
I can't tell you how many times I have been asked about our choice of wire size.

History and experience has led many PoCo's to their choice of wire size. How many houses pull 150 amps continuously? If you get down to it, a #4 Al. is good for 115 amps, how many houses will pull that much at one time? Especially with gas...
 
Besoeker said:
I'm sure that's true.
But it just doesn't excuse the the horribly untidy state of the wiring in my opinion.
Butt connectors are bad enough but just having them hanging it mid air - ghastly.
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I guess it could have been neater. The butt connectors are filled with inhibiting compound, and the covers are filled with a mastic on the new service. The old services are connected with "H" taps and taped. they also are filled with inhibiting compound.
 
Hv&Lv said:
I guess it could have been neater. The butt connectors are filled with inhibiting compound, and the covers are filled with a mastic on the new service. The old services are connected with "H" taps and taped. they also are filled with inhibiting compound.
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I'm not suggesting that it won't work or is unsafe.
Just that it looks horrible.
 
480sparky said:
Why loose sleep over someone else's sloppy work?
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I won't.
But a slightly more serious side is that it is sloppy and cheap.
It's easy to do sloppy and cheap.

But not so good if your customers expect neat and tidy work.
 
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POCO is not designing things to same standards as we do inside buildings.

How many times have you run into old services with fuseboxes and 30 amp edison fuses protecting 14AWG conductors? The conductors can carry twice what we typically design them for without blowing the fuse, yet the place did not burn down, but there is a chance someday it could - especially after something gets deteriorated enough.

Now place that conductor outdoors in free air. Even if it is overloaded it is not much of a threat to burn down the property. The main risk is loss of power if there is a failure.

I had a school building one time which we added a fair amount of air conditioning load. I had some concern over whether or not there was enough transformer as well as service lateral to handle the increased load - POCO happened to own and maintain this lateral. I believe they had 350 aluminum conductors supplying at least 600 maybe 800 amps of service equipment between two different buildings. That was already undersized according to NEC. They figured what past demand had been and added new load and determined they could just change the aluminum to copper and keep it same size and they would be fine. I remember one factor in the calculation that you do not run into with NEC was how long the load was expected to be at peak demand as well as how long it was expected to have a "cool down" period. If I was to install this lateral it would have to been at least 2 parallels of 350, and maybe even 3 parallels to meet NEC - would really depend on what actual load calculations were. Still works fine today - the additional AC load is only for a few weeks every fall right when school starts and only for maybe 5-6 hours per day when it is still pretty warm outside. If it ever does fail it is completely outside of a brick building - main problem for the school will be loss of power and not a building starting on fire.
 
Besoeker said:
I won't.
But a slightly more serious side is that it is sloppy and cheap.
It's easy to do sloppy and cheap.

But not so good if your customers expect neat and tidy work.
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That is true. Only thing here is... no one paid the PoCo to do the work.
 
iwire said:
They have a much better idea of what the true load will be.
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Just how do they know that.. :blink:

I do a service change and send the temp. certificate to the POCO.. no load letter is required..

They have no idea what load has been added and it is more about "pot luck" than adding numbers together..

Their biggest drop is 1/0 AL for any overhead size service.. but to be fair.. I have not seen one of their drops melt.. :)
 
480sparky said:
So no one ever pays their electric bill?
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Sure. I see your point, but that was meant it the context of Besoeker's post. You also pay your gas bill, phone bill, cable bill, etc., yet you have no say in how the connections are made. There is the alternative, If the owner doesn't like it, the PoCo can remove the wires...


If a customer is paying me directly to do work for them, they have a say in how the work is done and how it looks. If I don't like that fact, I am free to look for work elsewhere...
 
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