Struggling with wiring a dimmer switch, can someone help me figure out what to do with the red and blue wires?
Asked by Mattie Mckinney 
3 months ago
Last Updated: August 28, 2024
Hey there!
Can you help me figure out how to connect this dimmer switch?
I’m a bit confused by the red and blue wires.
Contact an electrician
Hey, does this team happen to have any electricians?
Hire an electrician before attempting something and risking a fire in your house
Exactly, and we earn our living as electricians, so it’s best to call one.
Wynne What’s the purpose of this group then? 🤷🏼♂️
This group is meant for the community. It’s not a place for homeowners to bombard us with questions. Sometimes it’s better to hire a professional than to cut corners.
For me it is about showcasing our work and supporting each other, especially the new guys in the industry. I don’t mind if non-electricians seek advice or simple solutions for their projects. I enjoy being friendly, but it can be frustrating when people ask for extensive help without wanting to hire a professional. This is how I make a living and it’s disheartening when people undervalue that. Sometimes I may not have the best attitude, but it’s because the situation can be overwhelming.
Not for you.. haha
I think the red and black wires are for the line/load and should be connected to the black wire on the dimmer. The neutral and blue wire go to the neutral, right? And of course, the ground wire goes to the ground. ood luck, I hope nothing gets blown off the wall.
Based on what I can tell, if the current switch is wired correctly, you should connect the green wire to the bare wire with a jumper to the box, the white wire to the blue wire, the line to the red wire, and the load to the black wire.
Hey Robert, not trying to be critical. Just curious, what makes you think the power is connected to the red wire?
Hey Jody, check out where the red wire is connected. It leads to the blue neutral wire. The black wire runs up the wall to power the light.
I see what Robert is talking about – I think the black wire is probably linked to the switch leg going up to the top of the box.
Got it, up to the light. Thanks, should’ve realized that on my own haha🤦♂️
I noticed that the red and blue wires come in from a conduit at the bottom of the box, while the white and black wires are connected to a x cable at the top. It could be the opposite way around, but that was just my initial thought.
The important thing to remember is that the line and load stickers on the dimmer don’t make a difference as long as you connect one black wire to the line and the other black wire to the load. Then connect the white wire from the dimmer to the white or blue wire in the box, and the green wire to the bare ground wire.
If it doesn’t make a difference, why do they bother mentioning line and load separately?
That makes sense now. Thanks for clearing that up for me!
The instructions make it clear that both line and load should be connected to the black wires, without specifying which is which. However, they do mention that white is the neutral wire and green is the ground wire.
Absolutely right.
In this case, the switch leg is indicated by black, red represents the feed, and blue signifies neutral.
Join them all together
It’s important to approach this situation seriously and seek professional help.
Called someone a Jackass.
Have you thought about reaching out to an electrician?
Maybe you could try giving your boss a call?
It doesn’t seem like that will work, let’s try to find a neutral option.
Anders oh man, this comment is even more cringeworthy than the actual post itself.
Anders yeah, I always thought white was more neutral than blue.
You know, blue is never considered a neutral where I am, but white can definitely be seen as hot. What do you think?
I probably shouldn’t be commenting in my current state of mind anyway.
Two-thirds of the planet uses blue as neutral, and many end-user devices in the US come with a blue neutral wire. While it may not be the case here, it’s not something to lose sleep over.
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Make sure to use a digital volt meter to differentiate between the hot and neutral wires.
Imagine all the wires have the same color and test each one individually for grounding purposes.
You might want to contact an electrician to properly measure and determine the purpose of each wire.
In this case, the red wire is the line, so you should connect it to one of the black wires on the switch. The black wire is the load, so connect it to the other black wire on the switch. The blue wire is the neutral, so connect it to the white wire on the switch. Finally, the green wire should be connected to the bare copper wire.
Didn’t really matter much in this case, but how can you be sure that the red wire is the line and the black wire is the switch leg?
Mentioned that for the switch to function properly, the wiring in the conduit from the bottom has been in place longer than the romex from the top. He has encountered similar situations where the conduit wire served as the power wire in the past, some of which were previously used as receptacles.
Reds always hot, connect it to the black wire labeled (line). The black running up the wall should be connected to the black labeled load. The switch should be clearly labeled so you know which black is line and which is load. Blue is neutral, and green goes to the bare wire.
If you’re not sure, it’s better to seek professional help rather than relying on guesswork from strangers who are not present. Contact an electrician to be safe.
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I can do it for you for $120.
You should consider hiring someone who can interpret the diagram
Just to clarify, the red wire carries the hot current, blue is for neutral, and black is either the load or the return to the light.
I’m not entirely sure what that blue wire is for. It might be a neutral wire. It’s possible that someone was switching one part of a 240-volt circuit. You should use an electrical meter or consider hiring an electrician.
You’ve got all the necessary wires for this setup. It seems like blue is the neutral (grounded conductor) coming in, red is line, and black is load (switch leg). Connect the black from the dimmer to black, and the other black to red. The white wire from the dimmer must be pigtailed to the blue/white. round the bare wire to green. It’s always a good idea to double-check the wire connections and ensure that the line, load, neutral, and ground are properly identified. Failing to do so could result in damaging your dimmer.
It would be helpful to have more information about the device… I can see a neutral, so you’re in trouble.
Round/neutral/line/load.