Need bedroom light to stop dimming when receptacle is put under load.
#1
01-20-23, 07:32 AM
Join Date: Dec 2008
Posts: 32
Upvotes: 0
Received 0 Upvotes
on
0 Posts
Need bedroom light to stop dimming when receptacle is put under load.
How do I stop this bedroom light from dimming when things are plugged in/turned on? I googled "capacitor in box for light dimming" and things like that but didn't find what I wanted. Is that a thing?
so I'm fixing up my parents mobile home after the last tenant left it pretty rough. In the small bedroom somebody had previously ran romex in that outside the wall conduit up to a cieling fan/light. Was a weird bulb base I didn't have so I never even used it. But I pulled some paneling, couple small holes in the cieling and I ran the wire in the wall to a new light. Had a compact florescent in it and all was good then I pulled the trigger on the skilsaw and it got really dim then came back to maybe 80% until I let off the trigger. Had planned on brighter bulbs anyways I so I put a 100w equivalent led and obviously the same thing happens except now after it dims it comes back full even with the tool running.
I know it's not a main panel/incoming voltage problem because I can run the table saw in the kitchen and big chop saw in the living room and no dimming occurs. There is a chance the lighting in there is on its own circuit while I know the bedroom light is tapped into the receptacle. I am pretty sure though while flipping breakers and watching lights and stuff that every room has lighting and receptacles intertwined on circuits.
I pulled all receptacles in the room and on other sides of shared walls and got rid of all backstabbed receptacles with new ones using side terminals. A few the wires came out real easy so I was hoping when I got it all back together a loose connection would have been my issue but it wasn't (or theres one on the circuit ahead of that bedroom I haven't addressed)
when I had back over I'm going to try and use my meter to figure out just how much drop there is at the light when I pull the trigger on a tool, but that's not going to help me figure out what to do. Any ideas?
so I'm fixing up my parents mobile home after the last tenant left it pretty rough. In the small bedroom somebody had previously ran romex in that outside the wall conduit up to a cieling fan/light. Was a weird bulb base I didn't have so I never even used it. But I pulled some paneling, couple small holes in the cieling and I ran the wire in the wall to a new light. Had a compact florescent in it and all was good then I pulled the trigger on the skilsaw and it got really dim then came back to maybe 80% until I let off the trigger. Had planned on brighter bulbs anyways I so I put a 100w equivalent led and obviously the same thing happens except now after it dims it comes back full even with the tool running.
I know it's not a main panel/incoming voltage problem because I can run the table saw in the kitchen and big chop saw in the living room and no dimming occurs. There is a chance the lighting in there is on its own circuit while I know the bedroom light is tapped into the receptacle. I am pretty sure though while flipping breakers and watching lights and stuff that every room has lighting and receptacles intertwined on circuits.
I pulled all receptacles in the room and on other sides of shared walls and got rid of all backstabbed receptacles with new ones using side terminals. A few the wires came out real easy so I was hoping when I got it all back together a loose connection would have been my issue but it wasn't (or theres one on the circuit ahead of that bedroom I haven't addressed)
when I had back over I'm going to try and use my meter to figure out just how much drop there is at the light when I pull the trigger on a tool, but that's not going to help me figure out what to do. Any ideas?
#3
01-20-23, 09:25 AM
Group Moderator
It sounds like something is limiting the current. When you start the saw it draws A LOT, dropping voltage for the circuit or the whole house.
That limit could be how much is being fed to the house. Many older properties have poor/little service in the modern electronic age. I've seen houses with main breakers as small as 60 amps. That doesn't leave much headroom if running AC, heat pump or electric heat, stove, dryer, water heater... That's easy to check by turning off all the 240v double pole breakers. That should cut the majority of the load. If the light still dims dramatically I'd look for corroded or loose connections.
Finding poor connections is where a thermal/FLIR camera very helpful. Their price has come down but they are still expensive. Check your local tool rental stores or big box to see if they have one for rent. Put the circuits under a heavy load (turn on oven, dryer, run hot water, turn on AC...). After a minute or two a poor connection will often shine brightly in IR as it heats up.
That limit could be how much is being fed to the house. Many older properties have poor/little service in the modern electronic age. I've seen houses with main breakers as small as 60 amps. That doesn't leave much headroom if running AC, heat pump or electric heat, stove, dryer, water heater... That's easy to check by turning off all the 240v double pole breakers. That should cut the majority of the load. If the light still dims dramatically I'd look for corroded or loose connections.
Finding poor connections is where a thermal/FLIR camera very helpful. Their price has come down but they are still expensive. Check your local tool rental stores or big box to see if they have one for rent. Put the circuits under a heavy load (turn on oven, dryer, run hot water, turn on AC...). After a minute or two a poor connection will often shine brightly in IR as it heats up.
#4
01-20-23, 11:03 AM
Join Date: Dec 2008
Posts: 32
Upvotes: 0
Received 0 Upvotes
on
0 Posts
Water heater and furnace are gas. House is mostly empty so right now the only electricity being used is 1 fridge, 1 water recirculating pump, 1 cordless tool battery charger. I just tested a few places in the room. Resting voltage is about 122.3 +/- .2 depending on which receptacle I probe. I'm using a belt sander which is labeled 5.3A to test right now. I don't know if that's startup or continuous (which I understand they take more at startup but this doesn't happen in the rest of the house). Anyways at the receptacle I'm plugged in to it drops to about 112 and then recovered and holds at 117. Same with the receptacle on the other side of the room. At the switch I'm only dropping to about 116 and recovering/holding just shy of 120. At the light socket it actually dips just into the 111s and holds 117/118. (Which I'll check those again because dropping 5 more volts over 7-8 feet of 14/2 sounds excessive. But I checked them once already and they seemed good)
just turned all 3 lights on in living room/kitchen and hit the trigger on my chop saw that says 15A on the sticker (12" saw) and unless you stare directly at the light you can't even tell there's a change because it's a split second and BARELY changes. And that receptacle will drop to about 115 and then hold 120. I can't check with the saw because I would have to move a TON of stuff to get the saw plugged in near the switch so I used the belt sander again with the 3 lights on in the main area (all different switches though) and probed 1 switch and I actually have 123.2v there and it only drops to 121 or so when I pull the trigger. I used up the pro pack of receptacles already so I'm gonna grab more and see if I can find a bad connection in another one that is upstream on this circuit and hope for the best. My uncle is going to move in here for a while and this room will be his office and it would be nice if the lights didn't dim when he turns on the computer, etc. And I would guess they have built in protection so that a little voltage drop won't kill his computer eventually but I don't know for sure.
just turned all 3 lights on in living room/kitchen and hit the trigger on my chop saw that says 15A on the sticker (12" saw) and unless you stare directly at the light you can't even tell there's a change because it's a split second and BARELY changes. And that receptacle will drop to about 115 and then hold 120. I can't check with the saw because I would have to move a TON of stuff to get the saw plugged in near the switch so I used the belt sander again with the 3 lights on in the main area (all different switches though) and probed 1 switch and I actually have 123.2v there and it only drops to 121 or so when I pull the trigger. I used up the pro pack of receptacles already so I'm gonna grab more and see if I can find a bad connection in another one that is upstream on this circuit and hope for the best. My uncle is going to move in here for a while and this room will be his office and it would be nice if the lights didn't dim when he turns on the computer, etc. And I would guess they have built in protection so that a little voltage drop won't kill his computer eventually but I don't know for sure.
#6
01-20-23, 02:00 PM
Group Moderator
The amperage printed on the appliance is the running current. The starting inrush, usually things with motors, will be higher. Seeing the lights dim briefly when hitting something big like a chop saw is normal. Seeing lights dim from a 5 amp sander is worth investigating.
It's a good sign that the lights in the rest of the house don't dim. Since the lights only dim in that one room when you start a power tool I'd start investigating those circuits for a bad connection. Most circuits are wired in series. The power goes from the panel to the first outlet. Then from that outlet to the next and so on. The bad connection will usually be at the outlet you are using or a connection upstream (towards the breaker panel). A bad connection downstream from the heavy load doesn't make the lights dim.
It's a good sign that the lights in the rest of the house don't dim. Since the lights only dim in that one room when you start a power tool I'd start investigating those circuits for a bad connection. Most circuits are wired in series. The power goes from the panel to the first outlet. Then from that outlet to the next and so on. The bad connection will usually be at the outlet you are using or a connection upstream (towards the breaker panel). A bad connection downstream from the heavy load doesn't make the lights dim.
#7
01-20-23, 04:12 PM
Join Date: Dec 2008
Posts: 32
Upvotes: 0
Received 0 Upvotes
on
0 Posts
It's an old mobile so it's crazy how much is on one circuit. 2 living room receptacles (shared wall with bedroom), bedroom lighting and receptacles, master lighting and receptacles, 1 bathroom receptacle(shared wall with master), rear porch light, and hall light ALL on a single 15A circuit...
I have now replaced every receptacle in the circuit with new parts using side terminals. I bypassed the bedroom switch just in case (even though it too was brand new). I wasn't sure about the factory pigtail on the lights connection to the light socket so I stole the hall light base to try and no change. My orbital with a 2.8A rating causes no dimming, but it's a soft start unlike my belt sander. I just realized though that the hall/porch lights were also on that circuit so I am going to get into that box... watch my issue be the LAST place I look... last note is I swapped the 14W led bulb for the old 13w cfl and it dims a bit but nothing close to the led(its literally like its off when it dims), all the fans are led lighting but could they maybe have some sort of capacitor built into the led driver that eliminates the dimming?
I have now replaced every receptacle in the circuit with new parts using side terminals. I bypassed the bedroom switch just in case (even though it too was brand new). I wasn't sure about the factory pigtail on the lights connection to the light socket so I stole the hall light base to try and no change. My orbital with a 2.8A rating causes no dimming, but it's a soft start unlike my belt sander. I just realized though that the hall/porch lights were also on that circuit so I am going to get into that box... watch my issue be the LAST place I look... last note is I swapped the 14W led bulb for the old 13w cfl and it dims a bit but nothing close to the led(its literally like its off when it dims), all the fans are led lighting but could they maybe have some sort of capacitor built into the led driver that eliminates the dimming?
#8
01-20-23, 05:11 PM
Join Date: Dec 2008
Posts: 32
Upvotes: 0
Received 0 Upvotes
on
0 Posts
Nope. Entire circuit has now been checked and I even swapped 2 breakers just for the hell of it. Still dims. Its a brand new pack of led bulbs and they are the dimmable kind... guess I could try non-dimmable ones or a different brand but since the cfl dims a bit who knows if it will change anything.
#11
01-21-23, 09:46 AM
Group Moderator
It is normal for voltage to drop when there is a load put on it, especially a motor load. I agree that checking connections at the house panel is a good idea but also check the connections at the outside disconnect which mobile homes typically have. Make sure to check all connections in both panels
