northern Illinois service responsibility

[MannyBurgos]

Hey everyone. We have a multifamily dwelling built in the 70's that has under service wires from the transformer to the main disconnect. The existing wiring is aluminum, under sized and is an overhead to underground installation. Who is responsible for fixing this issue? Comed (utility) or customer? This is in northern Illinois. Thanks all.

 

[Dennis Alwon]

Around here it would be the utility but they are always undersized per the NEC

 

[MannyBurgos]

Around here it would be the utility but they are always undersized per the NEC

Thanks. The problem here is that their undersized wires are actually causing the aluminum 350kcmil wires to burn up. We've already lost atleast a quarter of those aluminum strands and its bubbling a little ways further showing signs that there wont be any stopping of the overheat. I actually did a load calc on the property and we are at 430amps after demand factors and all.

 

[Dennis Alwon]

Thanks. The problem here is that their undersized wires are actually causing the aluminum 350kcmil wires to burn up. We've already lost atleast a quarter of those aluminum strands and its bubbling a little ways further showing signs that there wont be any stopping of the overheat. I actually did a load calc on the property and we are at 430amps after demand factors and all.

Some pocos require the contractor to install the wire from the pole to the house while others may make the ec install the conduit. Around here they will install it but if it needs conduit they ask us to do it because it is cheaper. Once they asked me to supply the conduit and they would install it. Generally we don't need to worry about it.

Where is the wire bubbling?

 

[MannyBurgos]

Some pocos require the contractor to install the wire from the pole to the house while others may make the ec install the conduit. Around here they will install it but if it needs conduit they ask us to do it because it is cheaper. Once they asked me to supply the conduit and they would install it. Generally we don't need to worry about it.

Where is the wire bubbling?

Not actual "bubbling" like a pan with hot oil and pork chops but developing some overheating bubbles a few inches from terminal at main disconnect. Main disconnect conductors on the picture is a straight shot to utility pole.

 

[Dennis Alwon]

That is a sign of a loose connection. It does not seem to have noalox on the old aluminum. That may help

 

[MannyBurgos]

That is a sign of a loose connection. It does not seem to have noalox on the old aluminum. That may help

I believe you are actually right and that did not pass my mind but after careful load calculation, I came up with 430amps single phase 120/240. This is actually after all demand factors and such. We know that aluminum 350 kcmil is not rated for that ampacity. Im using 75 degree column since terminals are not marked....

 

[ActionDave]

I believe you are actually right and that did not pass my mind but after careful load calculation, I came up with 430amps single phase 120/240. This is actually after all demand factors and such. We know that aluminum 350 kcmil is not rated for that ampacity. Im using 75 degree column since terminals are not marked....

Looks like a bad connection to me.
Whatever the load calc POCO wires are gonna be smaller. Did anybody check the actual load?

 

[MannyBurgos]

Looks like a bad connection to me.
Whatever the load calc POCO wires are gonna be smaller. Did anybody check the actual load?

There are a total of 8 units plus a house panel which serves common area lights one washer and one dryer. Eaxh dwelling has electric range, electric water heater and electric baseboard heaters (no a/c). There are currently (5) out of (8) vacant units right now. I did my load calc based on optional calc (220.80) which gave me 430amps. Standard calc gave me 582amps...

 

[MannyBurgos]

Looks like a bad connection to me.
Whatever the load calc POCO wires are gonna be smaller. Did anybody check the actual load?

Actual load is 98 amps on one leg and 89 amps on the other. 5 out of 8 units are vacant....

 

[MannyBurgos]

Looks like a bad connection to me.
Whatever the load calc POCO wires are gonna be smaller. Did anybody check the actual load?

im gonna give poco a call on Tuesday to come out and inspect and hand them my load calcs so do you think they will just blow me away?

 

[MannyBurgos]

Just in case here are the specs:
Total sq. Ft: 5,874va
Electric heat: 61,000va
Range: 12kva x 8
Dryer (only 1): 6720va
laundry (only 1): 1500va
House lighting: 700va
Water heater: 40,500va
2- 1/2hp 115v sump pumps:

 

[iwire]

after careful load calculation, I came up with 430amps single phase 120/240. This is actually after all demand factors and such.

The real load is always well below the NEC load calculations and the power company knows this.

They also do not use those calculations to determine the load, they use their many years of experiance and history of other buildings like that.

To me it looks like Dennis said, simply a loose connection.

 

[MannyBurgos]

Ok. Im going to go with a loose connection and poco wires are undersized which is acceptable to ahj.

This would be a first time repair for me for damage on a service entrance conductor. Is poco responsible for repair on this wire or is customer responsible for this? No slack available to cut and re-install. What's the best way to splice a piece of 350kcmil aluminum while still meeting 2011 Nec?

 

[ActionDave]

Ok. Im going to go with a loose connection and poco wires are undersized which is acceptable to ahj.

This would be a first time repair for me for damage on a service entrance conductor. Is poco responsible for repair on this wire or is customer responsible for this?

In my neck of the woods it would be the POCO. Every area is different and some POCO's are nicer than others.

No slack available to cut and re-install. What's the best way to splice a piece of 350kcmil aluminum while still meeting 2011 Nec?

Splice on some fresh conductor with a c tap or a Polaris connector. Might even be able to just re-insulate with some cold shrink.

 

[MannyBurgos]

In my neck of the woods it would be the POCO. Every area is different and some POCO's are nicer than others.
Splice on some fresh conductor with a c tap or a Polaris connector. Might even be able to just re-insulate with some cold shrink.

Thanks Dave! The polaris is nice. Already insulated

I'll be replacing 9 service panels and feeders at this property next week and kind of oversaw the condition of that main disconnect wire. The property owner had already signed contract when I came across this issue. My total cost to replace service entrance conductors from main disconnect to transformer pole was about $3500 which included trenching, providing a diesel generator, running underground pipe and pulling parrallaled conductors (based on my load calcs but as you said, poco does not care about load calcs. Now I know). I would have been out atleast $2500 from profit. The polaris will help me save that. I always thought we couldn't have any splices on sec.

 

[meternerd]

It depends on where the POCO decides they stop and the customer starts. If the panel is sealed, it's probably POCO. If it's really POCO installed wiring, they'll fix it their way. Probably won't be splices. As far as the wiring, look at the corrosion on the neutral. Moisture in the panel? No-OX or Alumalox is a must for aluminum conductors even when terminated in an aluminum rated lug. I agree with everybody else (for a change..). When melting is only near the connection, it indicates a high resistance contact, caused by either loose or corroded parts. Aluminum expands more than copper when heated so connections loosen and aluminum oxide is non-conductive. Put the two together and it's a recipe for a fire if not repaired. Especially at the service because the wiring is ahead of any overcurrent protection. Lots of trailer fires caused by aluminum wiring. Utilities use it because it's lighter and cheaper.

 

[iwire]

No-OX or Alumalox is a must for aluminum conductors even when terminated in an aluminum rated lug.

Can you cite any code reference requiring that?

 

[MannyBurgos]

It depends on where the POCO decides they stop and the customer starts. If the panel is sealed, it's probably POCO. If it's really POCO installed wiring, they'll fix it their way. Probably won't be splices. As far as the wiring, look at the corrosion on the neutral. Moisture in the panel? No-OX or Alumalox is a must for aluminum conductors even when terminated in an aluminum rated lug. I agree with everybody else (for a change..). When melting is only near the connection, it indicates a high resistance contact, caused by either loose or corroded parts. Aluminum expands more than copper when heated so connections loosen and aluminum oxide is non-conductive. Put the two together and it's a recipe for a fire if not repaired. Especially at the service because the wiring is ahead of any overcurrent protection. Lots of trailer fires caused by aluminum wiring. Utilities use it because it's lighter and cheaper.

The panel is not sealed. We shall see what they say when I call tomorrow. Hopefully they can take care of it at their expense. Otherwise, Im going to be putting a dog leg on my profit. I have a basic understanding of aluminum conductors, heat resistance, arcing and such and I KNOW that this wire is under-rated by about 150+ amps for this service. While I agree that this conductor shows signs of overheating, I wouldn't blame it entirely on a loose connection....

 

[jim dungar]

Realistically, the wire does not need to be larger than the fuses in the disconnect, by the way what size are they?

I would recommend that the overheated lug also be replaced.