Wow! Window A/C unit amperage

[General Lee]

Yes, I have not checked the AMPS. My volt meter doesn't have that option. I will say when I have run the A/C nothing else was on other than an alarm clock. Stuff is plugged in but not ON. So even though 2 other small rooms are on the same circuit nothing was on. Something else I noticed, When the lights flicker they brighten back up after a second but do not seem to be full brightness because when I shut the unit off, I can notice they brighten up just a tad. I'm not liking a 6 volt drop at the plug when the unit is running. I bought the A/C for emergency power outages but wanted to try it out to have a cooler bedroom while I sleep. I think I'm gonna take it out and just use for power outages.

You guys have been alot of help, but I'm still unsure if I have a problem. I don't know much about electricity and not sure how to do in depth testing.

 

[General Lee]

Not knowing exact model but 8,000 btu likely takes 800w running (6 2/3 amps) BUT on startup depending on the quality of your AC guess that these numbers would momentarily double to 1600w or about 15a.

Keep as much powered down as possible and everything else off if you can at startup.

It is a Brand new Kenmore 8,000 BTU. Box says 15 amps, sticker on unit says 7 amps/ 740 watts.

 

[k0ua]

Yes, I have not checked the AMPS. My volt meter doesn't have that option. I will say when I have run the A/C nothing else was on other than an alarm clock. Stuff is plugged in but not ON. So even though 2 other small rooms are on the same circuit nothing was on. Something else I noticed, When the lights flicker they brighten back up after a second but do not seem to be full brightness because when I shut the unit off, I can notice they brighten up just a tad. I'm not liking a 6 volt drop at the plug when the unit is running. I bought the A/C for emergency power outages but wanted to try it out to have a cooler bedroom while I sleep. I think I'm gonna take it out and just use for power outages.

You guys have been alot of help, but I'm still unsure if I have a problem. I don't know much about electricity and not sure how to do in depth testing.

Well the screw tightning thing I talked about wont cost a dime.. just a little time. and is not dangerous. as long as you find the right breaker and flip it off. Also would not hurt to take the breaker out and push it back in too. I have seen breakers have a little corrosion on the lugs.. tighten the wires on the breaker and Neutral bar, and tighten all the outlets that run on that circuit.. cant hurt a thing. flip the breaker back on and measure your voltage drop.. If it is not less, Well you are just out a little time that is all. If it fixes it, you are one happy cool camper..

James K0UA

 

[General Lee]

Well the screw tightning thing I talked about wont cost a dime.. just a little time. and is not dangerous. as long as you find the right breaker and flip it off. Also would not hurt to take the breaker out and push it back in too. I have seen breakers have a little corrosion on the lugs.. tighten the wires on the breaker and Neutral bar, and tighten all the outlets that run on that circuit.. cant hurt a thing. flip the breaker back on and measure your voltage drop.. If it is not less, Well you are just out a little time that is all. If it fixes it, you are one happy cool camper..

James K0UA

I can handle that, I've changed out plugs, light switches, etc before. Never have removed a breaker though.

 

[CurlyDave]

I can handle that, I've changed out plugs, light switches, etc before. Never have removed a breaker though.

If you have never removed a breaker, write down the brand of the breakers and go down to a big box home improvement store. Practice installing and removing a breaker a few times with their new, unpowered ones.

It is not difficult at all, but it helps to know exactly what should happen.

 

[k0ua]

I can handle that, I've changed out plugs, light switches, etc before. Never have removed a breaker though.

On the breaker you will have a screw terminal that loosens a clamp the the black wire is clamped into.. AFTER switching OFF the breaker, you can remove this black wire.. and gently pry on this end of the breaker to lift it from the buss bar. It will normally have a "tang" holding the other end and you are prying it off of the HOT buss, and it will fall out in your hand. Don't forget the buss is HOT at all times. unless you trip the main breaker to the house.. at which time you will be in the dark. Reinsert the breaker the same way, tang end in first, and lever the breaker down to contact the buss and seat firmly. Then reattach the black wire after you get done with all the outlets. Dont forget to check the white wire on this piece of romex under the screw on the Neutral bar, to make sure it is tight.. Flip breaker back on, and see that it holds, then go check your AC unit with your voltmeter to see if it still drops that much. Remember firmly tighten, but don't strip out any screws. Also remember that the curl of the wire to go under the screw goes in the direction of tightening the screw not in the direction to loosen the screw. In other words, as the screw tightens on the outlet, the wire curl or "circle" is getting tighter not looser. This procedure may or may not help, but it is worth a try. I have seen a lot of loose outlets and wires stuck in the back push in connectors of outlets. (only good for low current lighting branch circuits) and loose breakers and loose breaker screws.. it is up to you to do or not do.. Just be careful and think through everything before doing. Never become part of the circuit.. (been there, done that, didn't like it much) Good Luck.. Hope you get it fixed.

James K0UA

 

[k0ua]

If you have never removed a breaker, write down the brand of the breakers and go down to a big box home improvement store. Practice installing and removing a breaker a few times with their new, unpowered ones.

It is not difficult at all, but it helps to know exactly what should happen.

Excellent Idea!

James K0UA

 

[General Lee]

Do you guys think a 6 volt drop from A/C usage is to much?

 

[k0ua]

Do you guys think a 6 volt drop from A/C usage is to much?

The calculator (on the web ) for voltage drop, I put your parameters in, and it said. 1.44 volts. who knows for sure, but as already noted, I do not like the 14 gauge wire, for outlets, but it is what it is, but I am thinking 6 volts is too much.. for 70 feet, and your 6.5 amps Unless it is really drawing more current. (we need to know) or you have a high resistance joint.

James K0UA

 

[George2615]

It sounds like the OP's outlets and lighting are on the same circuit with multiple rooms on that circuit.
I also just bought an 8000 BTU window unit for my bedroom. The paperwork says to use a 15A circuit for power. Mine works fine and does not dim the light in the room since my lighting is on a different circuit. I don't see a problem for the OP using the AC at night so he can sleep since the room lights would be off anyway.

 

[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.