i bought a light fixture for my bathroom wall and the ground wire is aluminum and the existing ground wire in the wall is copper,so i would like to know if i can join them and if so,how?I assure you that if the light fixture was manufactured in the last 10 years, that ground wire is not aluminum. It may look aluminum but it isn\'t. aluminum small gauge wire for electricity has been illegal for many years. Why? It will create sparks eventually. --- So you can join that aluminum-looking ground wire to your house ground wire. (Make sure the connection is super tight - in case some nutcake put an aluminum wire for the light fixture ground) If you are still in doubt -- just replace the aluminum-looking ground wire at the fixture and replace it with a copper groung wire) btw: (aluminum is stlll allowed in heavy gauge wires from transformers to service entry panels (if they are greased at the service entry panel)Unfortunately, aluminum wire is often used on lower end fixtures as a cost saving measure : aluminum is cheaper than copper. Aluminum does pass code in North America, however, it\'s current carrying capacity is lower than copper, for a given cross section, and this must be taken into account when the manufacturer selects the wire gage. A ground wire should not actually ever carry current, except in extraordinary circumstances, such as your hot or neutral wires shorting out. Most likely, your fixture has a braided aluminum ground wire. It usually does not join well with solid copper wire using wire-nuts, but it can be done. If you chose this method, a touch of solder between the copper and aluminum can help the wire-nut threads get a grip and prevent the braided aluminum from shredding or twisting severely around the copper. Another option is to use a ground screw (typically a small, green-colored bolt) to secure the braided aluminum ground to the junction box. Of course this is only allowed if the junction box is metal! In this case, make a small loop with the aluminum wire and pass the screw through it. If the direction of your loop matches the direction of the threads, it should hold just fine while you screw in the ground-screw. Lastly, you can also use a Buchanan splice cap to join the two wires.This Site Might Help You. RE: can i join copper to aluminum? i bought a light fixture for my bathroom wall and the ground wire is aluminum and the existing ground wire in the wall is copper,so i would like to know if i can join them and if so,how?I doubt the ground wire is Aluminum, more likely it is tinned copper. Check by bending it, copper bends easier than aluminum, compare to the fixture wires. To connect copper wire to aluminum wire you need special conductive paste and connectors certified for CU/ AL.Yes, in this case. Long ago, house wiring was allowed with aluminum wiring. But, shorts were resulting from dissimilar metals touching, while conducting large current and in the presence of electrolitic moisture. The dissimilar metals touching was a problem due to electrolytic corrosion taking place- any time two dissimilar metals come in contact in the presense of an electrolytic solution, corrosion takes place. However, in your case, you are connecting a ground wire, that does not normally conduct- it will only conduct in case of a short or other failure to ground. You are not installing this in a place where salty, moist air is a concern (the electrolyte)- so, it\'s okay.Other related question