Residential voltage drop

Status
Not open for further replies.
N

nizak

Senior Member
Is voltage drop something that's taken into consideration by many here when it comes to long home runs in residential wiring?

I know it's a NEC recommendation and not a requirement.

- Garage circuits
- Appliance circuits
- Bathroom circuits

Just curious as to how other contractors handle this or aren't concerned at all.

I will usually set a sub panel at a mid point in the larger homes to compensate.

Any rule of thumb for distance using 14 and 12 NM?

Thanks
 
I think that the unwritten 100'/next size up for the conductors will work just fine. I find that most contractors wiring homes do not give this any consideration unless they're compelled to by another code besides the NEC.
 
I have usually had more concerns with the length of the main supply conductors and seldom had long enough circuit within the house to be concerned with VD. I normally don't run 14 AWG to the general use receptacles either though, just to fixed lighting.
 
#14 should not be run more than 200-250 feet to the furthest point and #12 not more than 300-350 to the furthest point. Do not exceed these values.
 
kwired said:
I have usually had more concerns with the length of the main supply conductors and seldom had long enough circuit within the house to be concerned with VD. I normally don't run 14 AWG to the general use receptacles either though, just to fixed lighting.
Click to expand...
Me too.

I wire all receptacles in #12, all lighting in #14
 
mbrooke said:
You want your breaker to actually trip during a short circuit.
Click to expand...
15/20 amp single pole QO and Homeline likely will trip somewhat quickly. (Don't know if they have same magnetic trip on the AFCI's)

Others (besides some discontinued ones) will usually take longer but should still trip presuming some weak connection doesn't fail first.
 
kwired said:
15/20 amp single pole QO and Homeline likely will trip somewhat quickly. (Don't know if they have same magnetic trip on the AFCI's)

Others (besides some discontinued ones) will usually take longer but should still trip presuming some weak connection doesn't fail first.
Click to expand...

True. But in general you want your circuit wired such that a short circuit doesn't take longer than 1 second (technically 0.8 seconds) to trip a breaker in regards to life safety.

In a bedroom I'd wouldn't be overly concerned (hardwood, no grounded objects) however in places where GFCI are required I would very much take this into consideration.
 
The mid house placed sub panel seems to be working out ok with my residential wiring.

Thanks for the input
 
mbrooke said:
True. But in general you want your circuit wired such that a short circuit doesn't take longer than 1 second (technically 0.8 seconds) to trip a breaker in regards to life safety.

In a bedroom I'd wouldn't be overly concerned (hardwood, no grounded objects) however in places where GFCI are required I would very much take this into consideration.
Click to expand...
You mean where GFCI's were required before maybe 2002 or so?
 
mbrooke said:
The thing is GFCIs fail, and should never be used to meet the requirements of an "effective ground fault current path"
Click to expand...
My point was more about GFCI is now required in places that never required it before some for not so great reasons.
 
mbrooke said:
You want your breaker to actually trip during a short circuit.
Click to expand...
With the wire lengths you gave, it would be very unlikely for a breaker to trip in its instantaneous range for a short circuit or ground fault at the end of the run.
 
don_resqcapt19 said:
With the wire lengths you gave, it would be very unlikely for a breaker to trip in its instantaneous range for a short circuit or ground fault at the end of the run.
Click to expand...


Great point, 100% agree.

I was only considering physiological responses thus going off of table 41.1.

1597518347044.png
 
don_resqcapt19 said:
With the wire lengths you gave, it would be very unlikely for a breaker to trip in its instantaneous range for a short circuit or ground fault at the end of the run.
Click to expand...
But should still trip on thermal function, just won't be nearly instantaneous time wise.

I'm used to seeing this with irrigation equipment, as many times am dealing with long runs. Usually dealing with 480 volts and time delay fuses as well.

Still is pretty rare to see more than 100 feet circuit length inside a dwelling.
 
Status
Not open for further replies.
Top