Receptacle Draw

[Alwayslearningelec]

I know dumb question. Trying to do a voltage drop calc. How do I know what the actual draw/load is for a standard 1P-20A duplex? They are mounted outside on pole and have about 7 per circuit. Thanks

 

[infinity]

1 amp or whatever the current is that Christmas lights use.

 

[Tulsa Electrician]

I would use 180 VA if nothing is listed.
Consider it a general use non dewelling receptacle.
180*7*1.25/120= 13.125 amps if for Christmas lighting.
Other wise 180*7/120= 10.5 amps
Another option use 16 amps on a 20 amp circuit assuming continuous.

Edit, Does the panel schedule show a total VA load for that circuit. If so divide that by 7.

 

[augie47]

Do you have any idea what the receptacles will be used for ? Christmas lighting vs food vendor trucks would make a big difference

 

[curt swartz]

My comment doesn't answer your question but.....
Why does an "Estimator" need to do voltage drop calculations? The projects electrical designer/engineer should be doing it.

 

[infinity]

There is no requirement to try and assume what might be plugged into a receptacle in the future. I wouldn't even bother to consider voltage drop.

 

[Strathead]

My comment doesn't answer your question but.....
Why does an "Estimator" need to do voltage drop calculations? The projects electrical designer/engineer should be doing it.

Seriously? The closest I have ever seen voltage drop calculations done on a branch circuit by an Engineer is a note that all receptacles over XXX feet must be #10. I do agree that I wouldn't do it as an estimator, but as a field person, I do it all the time.

 

[infinity]

My comment doesn't answer your question but.....
Why does an "Estimator" need to do voltage drop calculations? The projects electrical designer/engineer should be doing it.

I'm guessing that there is some boilerplate note stating the electrical contractor is responsible for ensuring that a certain level of VD isn't exceeded. For something like a receptacle circuit unless a load parameter is given there is nothing to prove that a 20 amp circuit with #12 conductors won't meet the level of VD specified.

 

[suemarkp]

An estimator may need to know if the conductors need to be upsized in order to price them properly, including the things that go with it like larger boxes and maybe more time. Maybe he's not working off architect or engineered plans.

 

[petersonra]

I would just calculate worst case which is 20 A at the last receptacle on the string. So if the string is 200 feet to the last receptacle, you would need #6 conductors to stay under 3% VD.

 

[letgomywago]

Up high or down low that answers part of the questions