14/2 NM cable resistance

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sparks1

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Massachusetts
From table 8, the resistance for coated copper # 14 at 75c is 3.39 ohms per k/ft, is this ok to use for 14/2 NM? If so how, far can you run this cable?
 
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sparks1 said:
From table 8, the resistance for coated copper # 14 at 75c is 3.39 ohms per k/ft, is this ok to use for 14/2 NM? If so how, far can you run this cable?
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How many load amps will it be carrying? Or do you want to assume that it will be the max allowed current?
Do you have specific voltage drop sensitivity or would you just want to follow the 2%, 3% informal guidelines?
 
Resistance of 14/ 2 romex

Resistance of 14/ 2 romex

From table 8 , 3.39 ohms per k/ft for # 14 copper 75c
Is this value ok to use for NM cable?
 
Sparks, please do not continue to start new threads on this topic, you can post questions in this thread.

Roger
 
GoldDigger said:
Southwire online calculator says 56 feet.
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Thanks for the calculator. In a residential application how would I figure the load and the number of outlets , lights, that would be allowed by code if I did not know the actual load?
Is it based on 3va per sq ft. Calc. Still won't give the number of outlets .It will however,give me the number of circuits. How many outlets? As they add resistance???
Or should I just stick to 80% of 15amp = 12 amps and stay with 56 feet to provide max load capacity to serve the possibility of having a full load of 12amp then I know i'm good??
Also would I use 3.19 ohms per k/ft from table 8 when calculating my esistance ????
 
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Resistance

Resistance

sparks1 said:
GoldDigger said:
Southwire online calculator says 56 feet.[/QUOTE
Thanks for the calculator. In a residential application how would I figure the load and the number of outlets , lights, that would be allowed by code if I did not know the actual load?
Is it based on 3va per sq ft. Calc. Still won't give the number of outlets .It will however,give me the number of circuits. How many outlets? As they add resistance???
Or should I just stick to 80% of 15amp = 12 amps and stay with 56 feet to provide max load capacity to serve the possibility of having a full load of 12amp then I know i'm good??
Also would I use 3.19 ohms per k/ft from table 8 when calculating my esistance ????
Click to expand...

Can anyone answer the above?
Click to expand...
 
You can put anything you want in the title or nothing at all.

You can put anything you want in the title or nothing at all.

buck33k said:
In a residential application the number of circuits is based on the 3va, not the number of outlets, and I don't believe the conductors in NM are coated.
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The neutral and phase conductors are coated (insulated) with the ground being bare (NM-B). A general rule of thumb is ten openings per home run. Like 4 receptacles and 1 light x 2 rooms. If you know you have a specific need though, that's another issue.
 
Chamuit said:
The neutral and phase conductors are coated (insulated) with the ground being bare (NM-B). A general rule of thumb is ten openings per home run. Like 4 receptacles and 1 light x 2 rooms. If you know you have a specific need though, that's another issue.
Click to expand...

Is coated insulated? I was under the impression it was tinned but can't find the reference in the code. Hopefully someone will post that.
Concerning the number of outlets, the load should be considered as the OP stated, but no limit on outlets being residential.
 
buck33k said:
Is coated insulated? I was under the impression it was tinned but can't find the reference in the code. Hopefully someone will post that.
Concerning the number of outlets, the load should be considered as the OP stated, but no limit on outlets being residential.
Click to expand...

I'm not aware of any modern nm that would be tinned- there has been talk that it was around ages ago, I know that some old bx was. Also coated to me generally means tinned- an wire encapsulated in insulation is ​insulated, not coated.:D
 
Coated to me always meant it had some type resin around it, like the coils in transformers.

EDIT electricity runs on the surface of wire right? So a chemical coating seems like it would impede the flow more than a plastic / rubber matter sitting on top of the surface.
 
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Tipytao said:
So tinned = coated? what is tinned?
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It's where the bare conductor itself is coated with a layer of tin. As was pointed out in the link was done a long time ago to protect copper conductors b/c of the corrosive nature of the old rubber insulation.
 
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sparks1 said:
Thanks for the calculator. In a residential application how would I figure the load and the number of outlets , lights, that would be allowed by code if I did not know the actual load?
Is it based on 3va per sq ft. Calc. Still won't give the number of outlets .It will however,give me the number of circuits. How many outlets? As they add resistance???
Or should I just stick to 80% of 15amp = 12 amps and stay with 56 feet to provide max load capacity to serve the possibility of having a full load of 12amp then I know i'm good??
Also would I use 3.19 ohms per k/ft from table 8 when calculating my esistance ????
Click to expand...
You can put as many receptacles as you want on a 15A or 20A circuit. More receptacles does not mean there will be more load on a circuit. This is one area where the code has not crept in and become a design manual.
 
Tipytao said:
Coated to me always meant it had some type resin around it, like the coils in transformers.

EDIT electricity runs on the surface of wire right? So a chemical coating seems like it would impede the flow more than a plastic / rubber matter sitting on top of the surface.
Click to expand...
Magnet wire in motors and transformers has a thin, tight, polymer insulation on it and it conducts great.
 
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