Using clustered bare copper ground wire for neutral on service feed

[byteharmony]

I noticed the old electric service I'm replacing uses bare copper instead of insulated wire for the neutral. This service is using 4 AWG wire, not sure if it's THHN, can't read the sides of it yet.

I'm upgrading to a 200 AMP service. I planned to use 3/0 THHN to comply with NEC code. A local electrician said for service feed you can use 2/0 instead because it's not commercial it doesn't require the 3/0. I had my AHJ inspector over and he said it was okay to use 2/0 as well.

Here's where it gets interesting.
I may run out of the 3/0 that I purchased and planned to use for the Neutral on the service feed. Can I swap out one 3/0 THHN neutral wire for five 4 AWG bare copper neutral wires braded together just to the meter socket?

Based on my calcs that would give me a larger conductor than 3/0, it would be the same thing used in the current service, it would save me a buck a foot on wire and it would be fun and be an interesting story. One concern I'd have is if it would be difficult to feed that cluster of strands into the connectors on both ends since they are not MFG stranded.

Here are the tools for my calcs:

https://www.v-cap.com/awg-calculator.php Cross Reference AWG to MM2 Cross Reference AWG to MM2 www.multicable.com

 

[timselectric]

Can I swap out one 3/0 THHN neutral wire for five 4 AWG bare copper neutral wires braded together just to the meter socket?

No
You can not use parallel conductors smaller than 1/0.
And a neutral can no longer be bare.

 

[byteharmony]

No
You can not use parallel conductors smaller than 1/0.
And a neutral can no longer be bare.

Tim, you're the best!

 

[CoolWill]

No
You can not use parallel conductors smaller than 1/0.
And a neutral can no longer be bare.

That's correct about the parallel conductors, but the neutral can still be bare on the service entrance side.

 

[timselectric]

That's correct about the parallel conductors, but the neutral can still be bare on the service entrance side.

The utilities part, yes. They have their own rules.
But not on the customer's side of the demarcation point.

 

[CoolWill]

The utilities part, yes. They have their own rules.
But not on the customer's side of the demarcation point.

Well, sorta. The service entrance neutral can be bare copper in a conduit or cable. The service entrance conductors include the conductors to the disconnect from the meter, which is on the customer side. So the neutral from the service drop from the utility, to the meter, all the way to the first disconnecting means can be bare.

 

[byteharmony]

The utilities part, yes. They have their own rules.
But not on the customer's side of the demarcation point.

Well, sorta.

Where is the line that separates the customer's side and the utilities side?

Does this "Okay to use bare copper" include stranding your own stranded wire? I get that in my house, no go on the bare wire for neutral, it has to be that way as the only bond allowed for ground is at the main panel, so neutral should never connect to ground outside of the main panel.

However, on the connection from the pole conductor neutral, which is a bare wire and has no separate ground, to my meter sockets (I have 2, one for charging me and one for PV generation, wish i had a bidirectional meter), to my first disconnect point - a fused AC disconnect switch, it would have been nice / cheap / interesting, made sense, to use bare wire.

This is great info, thx guys!

 

[CoolWill]

Where is the line that separates the customer's side and the utilities side?

Does this "Okay to use bare copper" include stranding your own stranded wire? I get that in my house, no go on the bare wire for neutral, it has to be that way as the only bond allowed for ground is at the main panel, so neutral should never connect to ground outside of the main panel.

However, on the connection from the pole conductor neutral, which is a bare wire and has no separate ground, to my meter sockets (I have 2, one for charging me and one for PV generation, wish i had a bidirectional meter), to my first disconnect point - a fused AC disconnect switch, it would have been nice / cheap / interesting, made sense, to use bare wire.

This is great info, thx guys!

The utility generally consider anything past the load side of the meter to be yours. But the NEC considers the entire run of conductors from the utility connection point to the first disconnecting means as "Service Entrance Conductors". NEC 230.41 sets the rules for SEC insulation.

As Tim pointed out, conductors smaller than 1/0 can't be parallel by code. But logically, bare copper wires braided together is no different than bare copper wires manufactured together somewhere else.

 

[byteharmony]

The utility generally consider anything past the load side of the meter to be yours.

This doesn't make sense, I have to pay for the meter box, the offset, the clamps, the rigid conduit, etc. It would seem to me to be the utility ends at the mast clamp, the service wires strung to the mast and the crimping they do to YOUR wires that come out of YOUR mast head.

But the NEC considers the entire run of conductors from the utility connection point to the first disconnecting means as "Service Entrance Conductors". NEC 230.41 sets the rules for SEC insulation.

Makes sense that there are different rules for service entrance than in the house: SEC

As Tim pointed out, conductors smaller than 1/0 can't be parallel by code. But logically, bare copper wires braided together is no different than bare copper wires manufactured together somewhere else.

Then would it follow that any wire larger than 1/0 must be an insulated wire then? My old service is likely 4 AWG, the new is a larger than 1/0 so it must have all conductors in a manufactured UL approved insulation.

Silly but presses the point, you can't stick the bare copper in PVC, that is still paralleled conductors due to the UL issue?

 

[timselectric]

Where is the line that separates the customer's side and the utilities side?

The point of demarcation (between the customer and utility responsibilities)
Is where the utility connects to the customer.
For an overhead drop. It's the connections at the top of the service.
For an underground service feeder. It's the connections to the top of the meter.

 

[CoolWill]

This doesn't make sense, I have to pay for the meter box, the offset, the clamps, the rigid conduit, etc. It would seem to me to be the utility ends at the mast clamp, the service wires strung to the mast and the crimping they do to YOUR wires that come out of YOUR mast head.


Makes sense that there are different rules for service entrance than in the house: SEC


Then would it follow that any wire larger than 1/0 must be an insulated wire then? My old service is likely 4 AWG, the new is a larger than 1/0 so it must have all conductors in a manufactured UL approved insulation.

Silly but presses the point, you can't stick the bare copper in PVC, that is still paralleled conductors due to the UL issue?

Parallel doesn't mean physically next to each other. It means electrically connected at each end. As in using a number of smaller conductors "in parallel" to make a larger conductor. Code doesn't allow that with conductors smaller than 1/0.

 

[timselectric]

Well, sorta. The service entrance neutral can be bare copper in a conduit or cable. The service entrance conductors include the conductors to the disconnect from the meter, which is on the customer side. So the neutral from the service drop from the utility, to the meter, all the way to the first disconnecting means can be bare.

You are correct. A bare neutral is still allowed. As a service conductor, before the N/G bond.
I haven't used a bare neutral in almost 40 years. Showing my age. lol
That said, I still wouldn't do it. Especially in metal conduit. Because if the neutral connection fails. The conduit becomes the conductor.

 

[CoolWill]

You are correct. A bare neutral is still allowed. As a service conductor, before the N/G bond.
I haven't used a bare neutral in almost 40 years. Showing my age. lol
That said, I still wouldn't do it. Especially in metal conduit. Because if the neutral connection fails. The conduit becomes the conductor.

Last time I bought large bare wire, for a delta ground, it was more expensive than the insulated wire of the same size. Besides just having it laying around, or maybe making it in a pinch like the OP, I'm not sure why anyone would use it for a service neutral.

 

[byteharmony]

if the neutral connection fails. The conduit becomes the conductor.

Interesting, but if the connection fails it's going to be at a connection point, which then disconnects the neutral. If it failed in the middle something serious happened to my 2" rigid conduit... at which point it's likely power to the neighboor hood is down via my utility shutting it down.

In my case, I'm doing a 200 AMP service feed.
My neutral is not smaller than 1/0, it's larger.
So i CAN then take my ground wire and parallel it from my meter (only place I didn't do with THHN yet) to where the wires are crimped at the mast head? - in my case, about 10 feet of wire.

 

[CoolWill]

so i CAN then take my ground wire and parallel it from my meter (only place I didn't do with THHN yet) to where the wires are crimped at the mast head? - in my case, about 10 feet of wire.

Are you talking about taking the earth ground up to the utility neutral crimp? If so, that is an NEC legal way of doing it, but is it OK by the utility? I know of one electric co-op that actually requires it that way, but you should check with your utility spec guide

 

[timselectric]

Interesting, but if the connection fails it's going to be at a connection point, which then disconnects the neutral.

This is when the conduit tries to carry the current. Because the conduit is bonded to the neutral at the meter and the main disconnect.
This will happen if the neutral connection is lost at the meter or main panel. But not if the utility connection fails.

 

[timselectric]

So i CAN then take my ground wire and parallel it from my meter (only place I didn't do with THHN yet) to where the wires are crimped at the mast head?

No
Your leftover "ground wire" is smaller than 1/0.

 

[byteharmony]

This will happen if the neutral connection is lost at the meter or main panel.

I was informed you only bond at the main panel, is it also at the meter?

No Junctions, solid wire (copper stranded 4 awg in my case)

No
Your leftover "ground wire" is smaller than 1/0.

Ahhh, the individual elements to be paralleled can not be less than 1/0 not the resulting conductor from being paralleled. Got it.

 

[timselectric]

I was informed you only bond at the main panel, is it also at the meter?

Yes
At and before the main service disconnect.
Nowhere else, after the main service disconnect.
Before the main, isn't discussed much here. Because most people are not building a service. They are only adding on, after the main.

 

[byteharmony]

I'm 30 feet short on my service wire so THHN from the store is what it's going to be! Thanks so much for your help guys!

most people are not building a service. They are only adding on, after the main.

What about grid tie microinverters? I thought they made up the majority of solar installs. My utility requires those to be on a separate meter that is connected to the grid in between the utility feed revenue / charging for power meter. As I understand it that requires people to change the service side to disconnect those conductors (which are hot, or wait until the utility comes and shuts them off), connect them to a Polaris or some other kind of junction device to parallel connect those wires to a PV meter.

My meters will be in series because of my sol ark requiring it. I know some other people who also have serial meters who have the solar on a breaker in there normal load center electrical panel.

Only in the case of doing a solar system on a breaker that has a meter after that breaker would you leave the service unaltered.

How common are these different forms of change?

This is seriously like a college course in solar engineering, you guys are the best! I love this form!