Home electricity question

[CalvinHobbes]

Our house was built in 2000. We recently got a portable heater to use in the master bedroom and when we turn it on, the lights in the room and in the bathroom dim until the heater turns off. The heater is rated @ 1500W.

Would adding additional circuit breakers and splitting the runs among the new circuit breakers help this?

 

[amdskip]

Usually a bathroom is separate from a bedroom. How many amp service do you have? 200 is pretty standard now and hopefully you have at least that. Is there room in your box?

 

[darkxshade]

No, your best bet is to sell your house and buy a bigger one that you can't afford with the works. It's the American way!

 

[LTC8K6]

I would put in a dedicated 20A 115V circuit for such a heater.

It's close to the limit for the 15A circuit by itself.

The fact that your lights are going dim means you need to quit using it.

 

[ViviTheMage]

check how many amp's its pulling..typically it'll flip your 20 amp breaker because your heater is 18-20 amps itself.

If I build a house, I want to do 30 amp breakers everywhere , expensive...but worth it.

 

[iamwiz82]

1500w / 120V is 12.5A. So you are pulling 12.5A on a circuit that is probably 15A max.

 

[IHateMyJob2004]

The dimming of your lights is because of voltage drop. Just google it. I think wikipedia even has a page on voltage drop.

Yes, a dedicated service would fix things.

A ranch is easy to upgrade. A colonial requires that you punch holes in the wall to get a run up to the attic. It's doable though. And can be done on your own. If you do it, you might as well run 2 or 3 runs to the attic for "future" and make them 20 amp runs (12 awg wire). Once you get runs into the attic, you can drop in new outlets wherever you want. Just use 20 amp outlets and you'll know what the "new" plugs are. Just terminate things properly in the attic. This is easily a DIY job and should cost $300 at most. Seriously though, do extra runs. You are already going to be punching holes in your drywall and the extra wire will cost $150 at most.

Or you can do a 60 amp sub panel in the attic. truth is, if I did new construction, I would make such a thing a requirement of the builder. Sub panels are trickier, but doable. It might be worth while getting an electrician to your house to do.

 

[BigJ]

Originally posted by: ViviTheMage
check how many amp's its pulling..typically it'll flip your 20 amp breaker because your heater is 18-20 amps itself.

If I build a house, I want to do 30 amp breakers everywhere , expensive...but worth it.

No, they aren't. They'll typically go up to 1550w. At 110v that's ~14A. At 120v, that's ~12.9A.

If you leave the heater on for an extended period of time, it will indeed trip the breaker (if it's 15A). When normal CBs heat up, they trip. This is part of why there's an 80% rule for loads running for extended periods of time (3 hours or more is considered a continuous load and that's where the 80% rule must be followed).

As for the OP, your bathroom and bedroom should optimally be split. AFCI protected circuit in the bedroom. 20A circuit in the bathroom.

 

[alkemyst]

Originally posted by: ViviTheMage
check how many amp's its pulling..typically it'll flip your 20 amp breaker because your heater is 18-20 amps itself.

If I build a house, I want to do 30 amp breakers everywhere , expensive...but worth it.

A bit dangerous too for normal wall circuits.

 

[ViviTheMage]

Originally posted by: BigJ

Originally posted by: ViviTheMage
check how many amp's its pulling..typically it'll flip your 20 amp breaker because your heater is 18-20 amps itself.

If I build a house, I want to do 30 amp breakers everywhere , expensive...but worth it.

No, they aren't. They'll typically go up to 1550w. At 110v that's ~14A. At 120v, that's ~12.9A.

If you leave the heater on for an extended period of time, it will indeed trip the breaker (if it's 15A). When normal CBs heat up, they trip. This is part of why there's an 80% rule for loads running for extended periods of time (3 hours or more is considered a continuous load and that's where the 80% rule must be followed).

As for the OP, your bathroom and bedroom should optimally be split. AFCI protected circuit in the bedroom. 20A circuit in the bathroom.

Kind of what I meant, you just had a nice story with yours!

Originally posted by: alkemyst

Originally posted by: ViviTheMage
check how many amp's its pulling..typically it'll flip your 20 amp breaker because your heater is 18-20 amps itself.

If I build a house, I want to do 30 amp breakers everywhere , expensive...but worth it.

A bit dangerous too for normal wall circuits.

 

[WarhammerUC]

my place was built in the 50s.. and man, I just rip out 10 15 amps and replaced with 20. They had so many junction boxes in the basement.. I reran a few home runs..

at one point, I was going to rerun the whole house.. too much work..

I only had 100 service amp.. i talked to an electrician, he told me not a lot of place in nyc has 200 service.. especially for a small 40x100 house

 

[Jeff7]

I'm to the point where I'd want one circuit per outlet box.

I did some wiring in my parents' basement, and it's amazing how much stuff is on one circuit. Flip one breaker and three rooms go out. And this is after we had circuits added shortly after we moved in. It was pathetic when we first got the house, and that was the upstairs that was pathetic. The basement might have had 2-4 circuits for the whole thing, which is around 1000 ft².

 

[waffleironhead]

---
Thank you for contributing nothing.
AnandTech Moderator Evadman

 

[CalvinHobbes]

Thanks for all the replies.

How many amp service do you have?

I'm not sure. Is this indicated on the power panel?

Is there room in your box?

Lots of room.



I'll check and see what can be done. I'd like to have a separate run just for my computer room.

 

[hanoverphist]

i love these kinds of threads, i always learn something new

 

[DrPizza]

OP, there's another possible problem: A poor connection somewhere. This would further increase the effect of the dimming when the heater is turned on. If you know the order of the outlets, you can test outlet to outlet to see if the problem suddenly becomes worse after a particular outlet. And, just as importantly, & if you're qualified enough to do so, check the connection in your breaker box. You can test 2 things: first, that there's enough torque holding the wire, and then, if there's a potential difference between the bar & the wire, signifying that there's a bad connection.


I've run 2 circuits to the bathroom. With a blow drier running while curling irons are heating up... You wouldn't want much else plugged in. I did it back when wire was cheap; 250' 12awg for $35 or 40.

Besides that, I personally like the 1 room - 1 circuit (except the kitchen = 3 circuits); then the breakers are much simpler to label. Plus, 1 circuit for all the ceiling fans/lights per floor.

Originally posted by: WarhammerUC
my place was built in the 50s.. and man, I just rip out 10 15 amps and replaced with 20. They had so many junction boxes in the basement.. I reran a few home runs..

at one point, I was going to rerun the whole house.. too much work..

I only had 100 service amp.. i talked to an electrician, he told me not a lot of place in nyc has 200 service.. especially for a small 40x100 house

since when is 4000 square feet considered "small"? And, I hope by ripped out, you meant that you replaced all the 14awg wiring with 12 awg, and not just the breakers themselves.

 

[Evadman]

If the lights are dimming, there is a bad connection somewhere, or just in general your electrical is fvcked up. The lights on the same circuit should not dim, even if you plug a 10,000 watt heater in.

The circuit breaker is not a current (or voltage) limiting device, it is a switch. Either the power is on, or the power is off (turned off or tripped). If the lights are dimming, something is pulling power in series (not allowed in any house circuit), you have a short, or you have a crappy connection somewhere.

And yes, you need more circuits. Hopefully you will find the crappy connection when you rerun the lines.

Originally posted by: CalvinHobbes

How many amp service do you have?

I'm not sure. Is this indicated on the power panel?

If it was built in 2000, it is almost surely 200. The top breaker (assuming it hasn't been fvcked with) will tell you the amperage rating of the box. Flipping that breaker will shut off your house

 

[dartworth]

My house was built in 1930 and contains the old knob & tube wiring. The main panel was upgraded to a modern electrical panel. We only have 100A service, but it works or us.

After moving in, I bought this book and started upgrading room by room. I also ran cat5e and coaxial throughout the whole house while I was at it.

I'm almost finished and feel it has been worth the effort. I really recommend that book too.

 

[CADsortaGUY]

Originally posted by: ViviTheMage
If I build a house, I want to do 30 amp breakers everywhere , expensive...but worth it.

And buy 30A rated switches and outlets? running 10 gauge wire to everything? Seems a bit overkill and would likely never be needed, especially when you can just run extra circuits. There should be nothing in your house that needs 30 amps of 115V. A garage - maybe but anything more than 20 amps would likely be 230V in the house.

 

[Modelworks]

Originally posted by: Evadman
If the lights are dimming, there is a bad connection somewhere, or just in general your electrical is fvcked up. The lights on the same circuit should not dim, even if you plug a 10,000 watt heater in.

:thumbsup:

Sounds like a contractor saved on the install by using smaller wire than what was to code.
I've seen it done before even on the lines from the meter to the breakers.

 

[AlienCraft]

Originally posted by: ViviTheMage
check how many amp's its pulling..typically it'll flip your 20 amp breaker because your heater is 18-20 amps itself.

If I build a house, I want to do 30 amp breakers everywhere , expensive...but worth it.

No you don't. You think you do, but you have no idea what you're talking about.
Just compare a roll of 10/2 w ground to a roll of 12/2 w gr, because all your wiring will need to be 10 ga. Then you'l;l have to buy switches and duplex outlets sized to handle 10 ga wire. They aren't cheap.
More than likely, what you want to do, is learn about residential wiring, the National Electrical C, and local electrical regulations, and then decide what is practical.

 

[Evadman]

Originally posted by: Modelworks
Sounds like a contractor saved on the install by using smaller wire than what was to code.
I've seen it done before even on the lines from the meter to the breakers.

that would do it. A smaller wire in the 16-18 gauge category would carry that much current, but heat up in doing so, thus adding extra resistance that would manifest as dimming lights. Then, later, a fire or short as the insulation melted and the wire shorted to the conduit.

 

[Jeff7]

Originally posted by: Evadman
If the lights are dimming, there is a bad connection somewhere, or just in general your electrical is fvcked up. The lights on the same circuit should not dim, even if you plug a 10,000 watt heater in.

So let's say I have the microwave running, and go into another room. The lights in the other room are on a separate circuit (microwave has its own circuit), and they brighten when the microwave turns off.

Is that like, dangerous or anything?

Most of the wiring in this building was likely installed not long after copper was discovered, though it does have a breaker box.

 

[Elstupido]

15 amp breaker should handle that heater easily, as long as there isn't a lot of other loads on that circuit.
Sometimes aluminum wire feeding the panel can loosen up at the terminations causing a lot of problems. This should be looked at by a qualified electrician. It's a simple matter of tightening up the termination screws.

 

[Modelworks]

Originally posted by: Jeff7

Originally posted by: Evadman
If the lights are dimming, there is a bad connection somewhere, or just in general your electrical is fvcked up. The lights on the same circuit should not dim, even if you plug a 10,000 watt heater in.

So let's say I have the microwave running, and go into another room. The lights in the other room are on a separate circuit (microwave has its own circuit), and they brighten when the microwave turns off.

Is that like, dangerous or anything?

Most of the wiring in this building was likely installed not long after copper was discovered, though it does have a breaker box.

That sounds like the feed from the meter or street is not large enough for the load.
I would start by contacting the utility company and tell them them what you are seeing.
If its that old it could be loose wiring.