Voltage Drop Issue

[1964element]

Stake ons

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[ActionDave]

This is pretty standard on jobs that we do without consideration of load. I think it is a crazy waste money in many cases and no one ever uses the real measured voltage in the calculation and the voltage rating of the equipment is always ignored as well. VD is the wild west in terms of understanding, implementation and enforcement.


View attachment 14092

That's nuts.

 

[jumper]

That's nuts.

The spec or the yahoo who wrote it? Both possibly?

 

[junkhound]

Did I read t;he OP correctly??

12V drop at 16 A. Even if #10, that is a 350 foot run ! Or am I math dyslexic this AM ?

If there are no 400 ft runs, I'd suspect the owner is using 2 different Harbor Freight meters ?

Suggest the owner reverse the meters, then he can get a Nobel prize for a new method of power generation?

 

[luckylerado]

Did I read t;he OP correctly??

12V drop at 16 A. Even if #10, that is a 350 foot run ! Or am I math dyslexic this AM ?

If there are no 400 ft runs, I'd suspect the owner is using 2 different Harbor Freight meters ?

Suggest the owner reverse the meters, then he can get a Nobel prize for a new method of power generation?

I get 190' installed length assuming #12.

Using 16 amps at 120 volts you are over the 3% at 57' and over at 90' using #10. You see how ludicrous it becomes. How often is your circuit length under 90' even in a small rough in.

 

[JFletcher]

This is pretty standard on jobs that we do without consideration of load. I think it is a crazy waste money in many cases and no one ever uses the real measured voltage in the calculation and the voltage rating of the equipment is always ignored as well. VD is the wild west in terms of understanding, implementation and enforcement.


View attachment 14092

How is this distance measured? I read it as physical distance, i.e, straight line. A receptacle 85' from a panel could have as little as 100' of actual wire length, or perhaps as much as 200' if it's at the end of a run of 9 other receptacles. Also, that spec, does it continue on past 85'? In other words, would say a 300' run require pulling #4 wire? If so, that's about the dumbest thing I've heard in a long time.

If engineers and cities demand 3% VD, then they also need to start speccing electrical rooms near the center of the building. How much wasted material, upsized conduits, wire, labor,etc would there be to meet a 3% VD using a 16A load on a 20A circuit? You cant even land #8 on a 20A breaker.

 

[luckylerado]

How is this distance measured?

Measured along the length of the circuit.

does it continue on past 85'?

It depends on the inspector frankly. My work is for our Army Corps of Engineers mainly and the level of understanding and common sense varies based on the QA staff. I can argue that a fractional HP motor rated at 110 volts does not need #6 conductors when it is 150' away but without fail every time I try to save the government money it comes back to bite my ass so I have learned to play their game and just shake my head. Your head would explode if you know how much money was tossed down the drain over VD when it is not necessary.

• :jawdrop:

would say a 300' run require pulling #4 wire?

Sometimes

that's about the dumbest thing I've heard in a long time.

Haha. I wish that I could say that.

You cant even land #8 on a 20A breaker.

That is easy. Try landing 500 MCM on a 100 amp breaker.

 

[sparkyrick]

Walmart is notorious for upsizing wires for branch circuits. Very common to see #6 or #8 spec'd for some receptacles.

 

[iwire]

Walmart is notorious for upsizing wires for branch circuits. Very common to see #6 or #8 spec'd for some receptacles.

:thumbsup:

For sure.

As long as the customer is paying it is profit not waste.

 

[1964element]

All prints show it but, how often is it done.
Many big box stores have sub panels.
Smaller ones I always pull in 12.
Would never get a job if it was bid for VD

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[sparkyrick]

All prints show it but, how often is it done.
Many big box stores have sub panels.
Smaller ones I always pull in 12.
Would never get a job if it was bid for VD

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Wally World hires an electrician that goes through stores and counts all the lights, rec's and pulls the panel covers off to see what size wire is on the breaker and see if it matches what the plan calls for. They make sure they are getting what they pay for.

 

[1964element]

This is true, and I have no great reply.
We have inspectors here that will check the furthest receptacles in residentials for drop.
So I know what's right and wrong but its hard to make a buck.

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[1964element]

I make it to the panel schedule. If it shows 30 they get 10.
The schedule will not take into consideration for VD.
Yes it will note VD but that does not change breaker size,
Most gear I receive will be custom breakers installed.

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