Garage feeder junction box bonding

WillK

Whether it is required or not, I would like to bond my 8x8 metal junction box in the house which is part of the run for the detatched garage feeder cable. On the hole where the feeder goes out through the wall, the junction box is lock nutted to rigid metal. On the hole in the junction box that is going to the panel, PVC conduit is used. I will be running a #8 ground conductor with the feeders. The outside conduit also has 3 #14 conductors for a 3-way switch which splice to 14-3 NM inside the junction box.

I want to bond the junction box using the #8 wire going through a ground lug I will install. Is it allowed to also put the ground from the 14-3 into the same lug? Or would I have to install a second ground lug for the smaller ground wire?

I assume I can't break the #8 to make a pigtail, plus I don't have big enough wirenuts on hand to accomodate 3 #8+ 1 #14.

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Please do NOT consider any "before" picture of my house as any kind of endorsement of any particular construction method. In fact, you should probably assume that if I post a "before" picture, I am posting it because I am soliciting advice on a proper replacement for one of MANY things done wrong by a previous owner.