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Install & Replace

Replacing a wall light fixture in bathroom. Ground wires are different sizes. Does it matter?

After pulling out a rather old (20+ years) light fixture, I'm ready to pop in the new one, however the ground/copper colored wires are not the same size. I took this pic to demonstrate the difference. The ground wire from the wall (the lower of the two wires) is much thicker and less pliable than the new fixture's wire (just above it). Of note, the picture uploaded sideways for no apparant reason.


I've heard different sized wires means different gauges and that I shouldn't potentially cross them. This is my first attempt to replace a light fixture so I'm fairly clueless as to these things. The old fixture doesn't seem to have had a ground wire.


Anyone know if I should/shouldn't connect them?


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Posted 2012-12-17T20:00:30+0000  by BobVilasson BobVilasson

Hey BobVilasson,


Thanks for your question and welcome to the community.


First off, I have to say your screen name is in my favorite top 5 names here!:smileyhappy:


Judging from your picture (thanks for the upload!), it looks as those 2 ground wires in question are exactly as you stated they were.


As long as you don't cross your bare copper wires with the hot and neutral (usually black and white) wires, you can use a ground connector to connect them together.


Even though they are different gauges, using a copper ground wire connector will be the best solution for safely connecting them. I generally connect the grounds first, then the hot and neutral wires for a light fixture.


Use the connectors shown and linked below to get the ground wires safely installed.

Gardner Bender Copper Crimp Connectors


Simply install the connector over the two wires guessed it...crimp them together. To do this, use a good pair of pliers and only do it once.


This bare copper connector will bring your copper wires together properly. Although this wire is exposed, a ground is a dead wire, used only if an overload exposed metal parts are connected to ground to prevent user contact with dangerous voltage if electrical insulation fails.


With that said, this kind of connector above is one of several you can choose, but I find it is the best for connecting ground wires. Another option is choosing a green wire nut connector, shown below.

Green Winged Wire Connectors


Use the options above to get the ground wires connected properly.


Was there any additional wiring  questions you may of have? Let us know, and we can be of further assistance.




Posted 2012-12-17T21:46:17+0000  by Joseph_HD_ATL

Thank you, Joe! I appreciate the detailed response. I do, in fact, have a few more basic questions...


  • The fixture came with enough of the caps in the pic below for all of the wires. They seem to be similar to the green winged connector, minus the wings. While I understand your opinion on favoring the crimp connectors, do you see any reason why I couldn't use there? Just making sure I'm not missing some vital info here. :smileyhappy:


  • Also, my original concern was more about having different sized wires connected. I gather from your response that it doesn't seem to be a concern. Am I right?

Thanks again!



Posted 2012-12-18T04:09:17+0000  by BobVilasson

Hi Bob Vilasson,


Yes, you can use the wire nuts that were supplied with the fixture for all of the wire connections, regardless of wire size. Wires of different gauge, or size, can be connected without concern.


Of course, consider the wire size when choosing which wire nut to use. The wire gauge and number of wires per connection will determine which wire nut to use. For instance, if you have 3 or 4 wire ends to be connected together, you will need a larger wire nut.


The copper crimp connector is non-insulated, so use it for the ground wire only. Wrap the base of all wire nuts with electrical tape after installing them for added safety.


Thanks for asking, be safe!




Posted 2012-12-18T13:23:58+0000  by Travis_HD_ATL

Great, that's the info I needed! Appreciate everyone's help! :)

Posted 2012-12-23T17:19:03+0000  by BobVilasson

No, the most important is that your hot leg and neutral are the correct size. I am not saying a correct ground of a #18 gauge is adequate for a #10 gauge Hot Leg but a #12 would be OK

Posted 2012-12-29T20:29:29+0000  by t-p
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