Conductor Sizing - Electrical - Page 2 - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 03-04-2013, 07:01 PM   #16
Member
 
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 6,976
Rewards Points: 2,048
Default

Conductor sizing


Can you re-install thicker wires from the weatherhead through the conduit down the side of the house? Nothing forbids installing thicker wires even though the pole transformer has a more limited amperes rating.

Two small a wire size runs into two issues: overheating and voltage drop.

Hanging in free air, wires can take more current before overheating becomes a concern. There is probably a chart somewhere that specifies the desired size for free air.

Voltage drop depends on the length of the wires as well as the thickness (and material). With 4 gauge copper and 120/240 volt service the run from the transformer to the meter can be up to about 115 feet (230' round trip) and voltage drop is within three percent for 125 amperes which is acceptable. Voltage drop is actually a little worse if you are drawing the maximum 125 amps (at 120 volts) on one side (from one leg) of the service and somewhat less on the other side.

There may be another one or two percent lost within the wiring inside the house and you want to keep the total below 5%.

It is rare that you will be drawing the full 125 amps on either side.

(4 gauge copper has about 0.25 ohm for 1000 feet. At all times in any portion of an electrical circuit including a section of wire, the voltage dropped in that section equals the current flowing through times the resistance.)

Advertisement

__________________
Forget super sized fries. The Washington Redskins could promote healthy eating with First Lady Obama by choosing a (red skinned) turnip for a mascot.

Last edited by AllanJ; 03-04-2013 at 07:33 PM.
AllanJ is offline   Reply With Quote
Old 03-04-2013, 07:04 PM   #17
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,162
Rewards Points: 2,116
Default

Conductor sizing


Quote:
Originally Posted by jlmran View Post
No it hasn't...

Have you read the other posts which state that these conductors are not the POCOs responsibility? Which posts are accurate?

The concept is...did the POCO install the wrong conductors, and is it the customer's responsibility to make it right?

Are these 4 awg conductors subject to the NEC or to the POCO rules? Does the fact that POCO installed them automatically exempt them from NEC requirements?
Did it get inspected? If POCO does the installation, then it doesn't abide by the NEC... end of story.


Besides all of that said, it will never be an issue in the real world....
stickboy1375 is offline   Reply With Quote
Old 03-04-2013, 07:32 PM   #18
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 979
Rewards Points: 502
Default

Conductor sizing


Quote:
Originally Posted by stickboy1375 View Post
Did it get inspected? If POCO does the installation, then it doesn't abide by the NEC... end of story.


Besides all of that said, it will never be an issue in the real world....
POCO installation:
Inspected = I don't know.

My installation of the 125 amp disconnect:
Permitted = yes.
Inspected = no.

Which will not be an issue? Compliance? Or wire melting? Or both?

Sometimes images help.
conductor sizing.pdf
Conductor sizing-conductor-sizing.jpg

Last edited by jlmran; 03-04-2013 at 07:41 PM.
jlmran is offline   Reply With Quote
Old 03-04-2013, 07:48 PM   #19
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,162
Rewards Points: 2,116
Default

Conductor sizing


Quote:
Originally Posted by jlmran View Post
POCO installation:
Inspected = I don't know.

My installation of the 125 amp disconnect:
Permitted = yes.
Inspected = no.

Which will not be an issue? Compliance? Or wire melting? Or both?
I don't see the issue since the POCO did the installation. The NEC is ridiculously overkill. Why didn't the job get inspected?

Last edited by stickboy1375; 03-04-2013 at 07:50 PM.
stickboy1375 is offline   Reply With Quote
Old 03-04-2013, 08:00 PM   #20
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 979
Rewards Points: 502
Default

Conductor sizing


Quote:
Originally Posted by stickboy1375 View Post
I don't see the issue since the POCO did the installation. The NEC is ridiculously overkill. Why didn't the job get inspected?
Good to know the NEC has lots of cushion...I guess.

No inspection occurred because I assume the inspector simply wants the permit money. Its in a rural location but it is incorporated into the town limits. Maybe he is lazy? I don't know...he is more than welcome to come inspect...he just doesn't do it. Write a check...get a permit filed...do the work. Small town culture.
jlmran is offline   Reply With Quote
Old 03-04-2013, 08:03 PM   #21
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,162
Rewards Points: 2,116
Default

Conductor sizing


Quote:
Originally Posted by jlmran View Post
Good to know the NEC has lots of cushion...I guess.

No inspection occurred because I assume the inspector simply wants the permit money. Its in a rural location but it is incorporated into the town limits. Maybe he is lazy? I don't know...he is more than welcome to come inspect...he just doesn't do it. Write a check...get a permit filed...do the work. Small town culture.
You really cant do anything anyway since the POCO did the work, if you are really concerned, call them and ask them their policy....
stickboy1375 is offline   Reply With Quote
Old 03-04-2013, 08:04 PM   #22
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,162
Rewards Points: 2,116
Default

Conductor sizing


Quote:
Originally Posted by jlmran View Post
Good to know the NEC has lots of cushion...I guess.
Do you really think you'll draw 125 amps anyway?
stickboy1375 is offline   Reply With Quote
Old 03-04-2013, 08:12 PM   #23
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 979
Rewards Points: 502
Default

Conductor sizing


Quote:
Originally Posted by stickboy1375 View Post
You really cant do anything anyway since the POCO did the work, if you are really concerned, call them and ask them their policy....
That's my question! I don't know if I'm really concerned or not. If I ignore it and the wires fail then that is a headache. But if that size wire really is technically and physically sufficient, then I might be inclined to not bother with it.

Don't worry...if anybody here says that the 4 awg is fine...and then the wires fail...I won't hold anyone here liable. I fully understand that the buck stops with the property owner.

I was just trying to reconcile the disparity between my interpretation of NEC versus what the POCO actually installed. And, it certainly is believable that the NEC has a moderate safety factor built into the data.
jlmran is offline   Reply With Quote
Old 03-04-2013, 08:16 PM   #24
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,162
Rewards Points: 2,116
Default

Conductor sizing


Quote:
Originally Posted by jlmran View Post
That's my question! I don't know if I'm really concerned or not. If I ignore it and the wires fail then that is a headache. But if that size wire really is technically and physically sufficient, then I might be inclined to not bother with it.

Don't worry...if anybody here says that the 4 awg is fine...and then the wires fail...I won't hold anyone here liable. I fully understand that the buck stops with the property owner.

I was just trying to reconcile the disparity between my interpretation of NEC versus what the POCO actually installed. And, it certainly is believable that the NEC has a moderate safety factor built into the data.

I've never had the POCO do an installation for me before, so im not sure what policy is in place for it, or what their standards are.... I do know the NEC does not apply to them, so really, if they do the install, i wouldn't lose to much sleep on it, if the place does burn down, you know who to sue.
stickboy1375 is offline   Reply With Quote
Old 03-04-2013, 09:40 PM   #25
Licensed Electrician
 
k_buz's Avatar
 
Join Date: Mar 2012
Location: SE Wisconsin
Posts: 4,343
Rewards Points: 2,006
Default

Conductor sizing


Is the meter socket rated for 125A? The versions we use are usually rated for either 100A or 200A.
__________________
__________________________________________________ ______________
Answers based on the National Electric Code. Always check local amendments.


k_buz is offline   Reply With Quote
Old 03-04-2013, 09:50 PM   #26
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 979
Rewards Points: 502
Default

Conductor sizing


Quote:
Originally Posted by k_buz
Is the meter socket rated for 125A? The versions we use are usually rated for either 100A or 200A.
Don't know at the moment. It is a 1-1/2 hour drive from my current location.
jlmran is offline   Reply With Quote
Old 03-04-2013, 10:02 PM   #27
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 979
Rewards Points: 502
Default

Conductor sizing


Second question:

Is a ground rod required or recommended at this pole location (see image above). When I installed the disconnect I simply used a split bolt to attach a bare copper wire to the existing copper wire which runs the length of the pole. Any obvious problems with ONLY doing that?
jlmran is offline   Reply With Quote
Old 03-04-2013, 10:06 PM   #28
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,162
Rewards Points: 2,116
Default

Conductor sizing


Quote:
Originally Posted by jlmran View Post
Second question:

Is a ground rod required or recommended at this pole location (see image above). When I installed the disconnect I simply used a split bolt to attach a bare copper wire to the existing copper wire which runs the length of the pole. Any obvious problems with ONLY doing that?
You need a code compliant GES at the disconnect, The pole is a structure... not sure what the copper wire you used a split bolt on does.... you need two rods by the way. You'll then need another disconnect and GES at the house.
stickboy1375 is offline   Reply With Quote
Old 03-04-2013, 10:21 PM   #29
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 979
Rewards Points: 502
Default

Conductor sizing


Quote:
Originally Posted by stickboy1375

You need a code compliant GES at the disconnect, The pole is a structure... not sure what the copper wire you used a split bolt on does.... you need two rods by the way. You'll then need another disconnect and GES at the house.
The existing copper wire is common on all rural poles (around here at least). It terminates at the bottom of the pole to either a metal plate or is rolled into a rough coil and stapled to the bottom of the pole. At the top of the pole it terminates at the neutral.

The house panel has a ground rod but does not have a main breaker. The panel is convertible and can receive a main breaker. Funny thing though...the house panel is mounted to the outside of the house. When you walk out of the house en route to the panel, you actually are at first physically closer to the pole disconnect. It's a shorter trip to the pole rather than the panel. But I understand the rules...I think.
jlmran is offline   Reply With Quote
Old 03-04-2013, 10:51 PM   #30
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,162
Rewards Points: 2,116
Default

Conductor sizing


Quote:
Originally Posted by jlmran View Post
The existing copper wire is common on all rural poles (around here at least). It terminates at the bottom of the pole to either a metal plate or is rolled into a rough coil and stapled to the bottom of the pole. At the top of the pole it terminates at the neutral.

The house panel has a ground rod but does not have a main breaker. The panel is convertible and can receive a main breaker. Funny thing though...the house panel is mounted to the outside of the house. When you walk out of the house en route to the panel, you actually are at first physically closer to the pole disconnect. It's a shorter trip to the pole rather than the panel. But I understand the rules...I think.
Yeah, every structure requires a disconnect, But i hear what you're saying... as far as the pole goes, I'm not 100% sure if what is at the pole is NEC worthy or not, the NEC does allow plates, but they have specifics to their design, so that would be hard to prove without sight unseen, same with the coil of wire, it would have to be 20' long not smaller than #2 AWG... so IMO, you would be forced to drive two 8' ground rods.

Advertisement

stickboy1375 is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Top of Page | View New Posts