Twist on wire connectors (C) Daniel FriedmanElectrical Box Ground Connections
Q&A on how to join electrical ground wires in the box

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How to make proper & safe electrical ground wiring connections in the box:

This article describes options for connecting a metal electrical box to the grounding conductor & connecting the grounding conductor to a fixture such as a ceiling light or ceiling fan.

Page top photo: ground wire for the ceiling fixture itself is connected to the grounding conductor by a twist-on connector while and a crimp connector connects all other ground wires inside the box. Grounds are marked by the green arrows. Click to enlarge this image and to see details. because this is a plastic ceiling-mount electrical box, a connection of the ground wire to the box itself is not required.

This article answers nearly all questions about residential ground wiring & electrical grounding safety in older homes.

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Electrical Box Ground Requirements & Methods

Reader Question On 2017-06-24 by TheDude: connecting the electrical grounds seems like excessive work?

Preparing for rough in. All outlet and switch boxes are spliced with appropriate pigtails.

Light fixture boxes were not touched but I have been told so strip and splice them.

Do I need to pigtail the grounds like the electrical boxes? Do I need to strip the wires and wirenut them as well? That seems like excessive work.

State = Minnesota

On 2017-06-25 by (mod) re: Metal boxes need to be connected to ground - ground wire connectors for wire-to-wire & wire-to box

Green ground screw on a two-gang metal electrical box (C) Daniel Friedman

Metal electrical boxes such as junction boxes, metal gang boxes, or metal receptacle, light or ceiling fan mounting boxes all need to be connected to the system ground, and of course all 120V and 220V circuit wire electrical splices must be made inside of a properly-sized and rated box.

Our photo above shows the manufacturer-provided green ground-screw intended for bonding this (wet location rated) two-gang metal electrical box to the grounding conductor.

If your electrical box does not include the ground-connecting screw you can either buy and use a green ground 3/8" x 10-32 threaded grounding screw from your electrical supplier or you may in some cases use a metal ground clip that bonds the ground wire to the side of the metal box. We show both of these devices in photos below.

Ground wire screw to connect metal box to wire 3/8" x 10-32 thread (C) Ideal ground wire clip for metal boxes (C)

Ground wires are bonded together in the box, a crimp is better than a twist on connector for that purpose, as a twist-on connector may crowd the box. In my photo below you can see my demonstration of having used a ground wire crimp-on clip to join two wires.

Types of ground wire bonding connectors for electrical wiring (C) Daniel Friedman

And a ground needs to be kept available to connect the ground of the light fixture to be installed. If you need an extra length of ground wire to connect the electrical box to a grounding screw on your light fixture or fan or other device, you might buy a pre-assembled 6-inch green ground wire provided with the ground screw (to connect to the electcrical box) on one end and a convenient u-clip on the wire's other end designed to connect to a ground screw on the fixture or device.

Garvin pre-assembled  8 inch ground conductor wire at

Below you can see our use of an orange twist-on connector to splice the ceiling light fixture's mult-strand ground wire to the circuit solid copper ground wire. Later we will of course push these wires carefully back up into the ceiling box.

Twist on connectors connecting both ground and hot wire ends at a ceiling light (C) Daniel Friedman




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