Wow! Window A/C unit amperage

[grsthegreat]

OK, i cant stand quiet any longer hehe


i AM a licensed electrical contractor...28 years now and counting.


As i stated previously, its all due to voltage drop. The room might only be 70 feet away, but if 3 rooms are wired together, then the wires are Daisy chained around all 3 rooms to the master bedroom. If all 3 rooms are say 10x10 plus the bathroom, you can easily have a run totaling 120 - 200 foot long when you add all the lengths of wire between outlets together. This is no 1.4 volt drop,

Using a true voltage drop distance of 150 feet (better guess than 70 feet in a daisy chain setup) i calculate an 11% voltage drop.

Mind you after 85 feet , there is a 5% voltage drop with #12 copper wire. But 5% is an acceptable level.

If i were you, i would run (or hire someone to run) a separate 20 amp circuit with #12 wires to a dedicated receptacle and call it good.


Without a clamp on amp tester, your just guessing. I have actual line testing equipment that cost me nearly $1,000 and with this you can actually SEE the drop in the current under load. A electrical test meter wont show you much, especially the starting load. A basic clamp on meter with a built in high test lock mode will help.

 

[k0ua]

OK, i cant stand quiet any longer hehe


i AM a licensed electrical contractor...28 years now and counting.


As i stated previously, its all due to voltage drop. The room might only be 70 feet away, but if 3 rooms are wired together, then the wires are Daisy chained around all 3 rooms to the master bedroom. If all 3 rooms are say 10x10 plus the bathroom, you can easily have a run totaling 120 - 200 foot long when you add all the lengths of wire between outlets together. This is no 1.4 volt drop,

Using a true voltage drop distance of 150 feet (better guess than 70 feet in a daisy chain setup) i calculate an 11% voltage drop.

Mind you after 85 feet , there is a 5% voltage drop with #12 copper wire. But 5% is an acceptable level.

If i were you, i would run (or hire someone to run) a separate 20 amp circuit with #12 wires to a dedicated receptacle and call it good.


Without a clamp on amp tester, your just guessing. I have actual line testing equipment that cost me nearly $1,000 and with this you can actually SEE the drop in the current under load. A electrical test meter wont show you much, especially the starting load. A basic clamp on meter with a built in high test lock mode will help.

Yep, I forgot about the extra length due to the daisy chaining. But I did tell him to run a new no.12 several posts ago.

Hey I guess that is why you are an electrician, and I didn't even play one on TV or stay at a Holiday Inn last night.

James K0UA

 

[General Lee]

Grsthegreat- you are correct, from what I can see in my unfinished basement, the wires appear to be Daisy chained together.

George2615- yes the lights and plugs are on the same circuit.

If anything came out of this thread I definitely learned some things. I won't have time to dig in and investigate the issue further until later on in the week. I'm not the original owner of the house so I have to deal with and fix what I was dealt.

 

[Ken]

James more mobile homes have burned because of the push in wiring in the plugs and seems they only have 2 circuits for the whole home. Wired like a christmas tree 1 outlet fail and the whole side of trailer is out.
14 guage wire and over loaded then the tv a/c in window and deep freeze with zip wired out window to back porch. Some times a wire to garage or parking area.
Dare suggest a change and get answer it always used to work this way.
The OP said 123 volts no load and little over 100 volts at 7.5 amps lights dim well yes probally glowing in the dark wiring.

I agree a total new 12/2 w ground rewired just for A/C to breaker box and added breaker
ken

 

[grsthegreat]

if you have an unfinished basement, running a new dedicated 20 amp home run should be real easy

 

[grsthegreat]

Yep, I forgot about the extra length due to the daisy chaining. But I did tell him to run a new no.12 several posts ago.

Hey I guess that is why you are an electrician, and I didn't even play one on TV or stay at a Holiday Inn last night.

James K0UA

thats ok... i only play with being a human being part of the time

 

[Ken]

O'k K7LN I read the post this morning and then spent most of the day keeping the wolf from getting inside.
OP did say 119.8 with volt meter. I memtioned 123 so 4 volts a big whoppie.
When the A/C was turned on a dimming of lights. then voltage settled to 113.8 I would be willing to comment it went a lot lower than the a little over 100 volts I stated.
but to be absolutly accurite i will agree to 119.8/113.8
ken
retired 17 years ago. with Master Electrican license.
and a 1st. class FCC license.
And have learned that the more I know the less I used to know.

 

[Larry Caldwell]

Something is not cool here??Dimming the lights with a 7 amp load???That does Not compute...After 6:00 in the evening the voltage here starts to drag down some. I have read it at 108 volts at peak demand here.A voltage drop can cause the amperage to climb a lot higher.. than at 120 volts..You said it does not trip the breaker.

Residential wiring typically daisy chains from outlet to outlet, and the outlets they use are stab-in receptacles where the only wire contact is a knife edge. Resistive losses build up over time as the copper oxidizes and heats. One of the first things I do when I buy a new home is to replace all the receptacles with spec grade screw terminal receptacles.

 

[jonyyuma]

Larry, I don't have any problem with this..I have replaced a lot of the cheap recepticles..Just trying to get the OP to really look at what he is doing?? Plus, I do not want to cause another -issing contest with any one. Electricity is one of the sore points here...for Advice with plenty of bull...Also one of the easiest ways to burn a house down...

 

[General Lee]

Jonyyuma- what do you mean "trying to get me to really look at what I'm doing"?

I realize something may not be right, one of the reasons I posted and looking for some advice. I haven't been using the unit and it's coming out tomorrow. Lots of members gave some hints and tricks to try and fix the issue and I learned some things.