If It's 80 Ft Long Wire (20amps) A Considerable Problem For Voltage Drop? - Electrical - Page 2 - DIY Chatroom Home Improvement Forum
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Old 04-25-2019, 10:45 AM   #16
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Re: If it's 80 ft long wire (20amps) a considerable problem for voltage drop?


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Originally Posted by bob22 View Post
Southwire has a calculator that when I ran it for 80 feet delivering 20 amps said you need 10 awg.
Site:
https://www.southwire.com/calculator-vdrop
Southwire is in the business of selling wire.

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Old 04-25-2019, 11:04 AM   #17
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Re: If it's 80 ft long wire (20amps) a considerable problem for voltage drop?


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Originally Posted by bob22 View Post
Southwire has a calculator that when I ran it for 80 feet delivering 20 amps said you need 10 awg.
Site:
https://www.southwire.com/calculator-vdrop
Makes sense, since with a continuous 20A feed, you would need a 30A circuit
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Old 04-25-2019, 11:20 AM   #18
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Re: If it's 80 ft long wire (20amps) a considerable problem for voltage drop?


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Originally Posted by bob22 View Post
Southwire has a calculator that when I ran it for 80 feet delivering 20 amps said you need 10 awg.
Site:
https://www.southwire.com/calculator-vdrop
Ok now this got me confused.
I can't do a #10 wire as I'm doing a junction box, as both side the wire should be same and I can't change what's in the wall now. If I'm having a voltage drop issue then I have to move the AC condensor and run another conduit from the main panel and do a subpanel. I was under impression yesterday that #12 wire should be ok for 80 feet and no worries at all.
(A.C. wires are thicker because the breaker is larger than 20 amp)

Thanks
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Old 04-25-2019, 11:26 AM   #19
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Re: If it's 80 ft long wire (20amps) a considerable problem for voltage drop?


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Originally Posted by rockman413 View Post
Why your calculation is very different from KPD's (see the 2nd or 3rd post)
I think I know why....truth be told it is correct to say there is a 2.5V drop to the load. However, there is a 2.5V drop from the load back to ground. This results in a 2.5V ground offset so if you measure your voltage across your device you would see 115V. However the potential to the device is 117.5V.
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Old 04-25-2019, 12:38 PM   #20
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Re: If it's 80 ft long wire (20amps) a considerable problem for voltage drop?


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Originally Posted by Sdiver2489 View Post
I think I know why....truth be told it is correct to say there is a 2.5V drop to the load. However, there is a 2.5V drop from the load back to ground. This results in a 2.5V ground offset so if you measure your voltage across your device you would see 115V. However the potential to the device is 117.5V.
Got it. But why I'm seeing people saying that could be problem and ask me to use a thicker wire? I'm so confused...
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Old 04-25-2019, 01:02 PM   #21
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Re: If it's 80 ft long wire (20amps) a considerable problem for voltage drop?


Problem is, as far as I can tell, we still don't know what the op is trying to do.

What is the load? A/C?

What's the rated voltage and current of the load?

Unlikely the rated current is 20A but if it is that's quite different.

Without this basic info this is all a waste of time.
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Old 04-25-2019, 01:05 PM   #22
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Re: If it's 80 ft long wire (20amps) a considerable problem for voltage drop?


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Originally Posted by CodeMatters View Post
Problem is, as far as I can tell, we still don't know what the op is trying to do.

What is the load? A/C?

What's the rated voltage and current of the load?

Unlikely the rated current is 20A but if it is that's quite different.

Without this basic info this is all a waste of time.
Ok, most load would be home devices such as cell phone charger, TV, computers, etc. (kitchen stuff is on another subpanel already)
Pool Pump which I guess has a thicker wire
AC units which has a thicker wire

So it looks like it's only the home devices that's on the #12 wire.
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Old 04-25-2019, 01:08 PM   #23
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Re: If it's 80 ft long wire (20amps) a considerable problem for voltage drop?


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Originally Posted by rockman413 View Post
Ok, most load would be home devices such as cell phone charger, TV, computers, etc. (kitchen stuff is on another subpanel already)
Pool Pump which I guess has a thicker wire
AC units which has a thicker wire

So it looks like it's only the home devices that's on the #12 wire.

So are you talking about 3 circuits?
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Old 04-25-2019, 01:10 PM   #24
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Re: If it's 80 ft long wire (20amps) a considerable problem for voltage drop?


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So are you talking about 3 circuits?
3 kinds of circuit:

1st kind: Home devices such as cell phone charger, computers, TV, excluding kitchen stuffs (already on another subpanel)

2nd kind: Pool Pump, probably have a thicker wire which has no worries over long distance.

3rd kind: AC units, have a thicker wire which has no worries over long distance.
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Old 04-25-2019, 01:26 PM   #25
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Re: If it's 80 ft long wire (20amps) a considerable problem for voltage drop?


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Originally Posted by rockman413 View Post
3 kinds of circuit:

1st kind: Home devices such as cell phone charger, computers, TV, excluding kitchen stuffs (already on another subpanel)

2nd kind: Pool Pump, probably have a thicker wire which has no worries over long distance.

3rd kind: AC units, have a thicker wire which has no worries over long distance.
This is like pulling teeth to get info to give a reasonable answer.
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