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.

Electrical Box Ground Requirements & Methods

On 2020-03-28 by Doug - bare electric ground wire run through building walls

Thanks. There are bare #12's going into the sub-panel and perhaps into the SE panel. The Fed-Pac StabLok sub-panel was installed without a ground bar

(because the feeder cable and all the branch cables have no grounding conductor). So the panel enclosure itself is not even grounded. A bare #12 goes into a hole in the sub-panel but is not actually connected, not sure yet what is going on there.

Maybe the bare #12 is attached to a water pipe under the house. We're replacing the sub-panel and will provide a proper ground wire to it from the SE panel. (Also replacing the SE panel.)

This Q&A were posted originally

at ELECTRICAL INSPECTION, DIAGNOSIS, REPAIR

On 2020-03-28 - by (mod) -

I'd have preferred an 8/3 WG (With Ground); or if running a separate ground wire, though bare is permitted,

IMO it's safer to use an insulated copper wire so that there's no chance of accidentally electrifying some bystanding component like a water pipe should a short to ground occur. At least take care in routing.

On 2020-03-28 by Doug

See pic of ground wire. I think the wire was added in the kitchen area to ground the appliances (in 1958).

In some cases, it's in the studs, elsewhere on the surface of the stud (that is, between stud and sheetrock).

But we're running a new 8/3 cable w.ground, from the SE panel to the kitchen for a new 40A oven. So we'll run a new bare #12 from the oven junction box to the kitchen outlets (which are fed from the SE panel), as permitted by NEC, and abandon the old ground wire.

On 2020-03-28 - by (mod) -

Doug I might think that bare ground wire is OK for "something" but I don't know what.

IF you can follow the wire to an electrical box we can see the connections there. E.g. a metal box might be grounded to this wire AND the same wire might be extended to ground connection screw on the device such as a switch or electrical receptacle.

At the other end we'd expect to see the wire connected to the ground bus/neutral bus in the electrical panel.

If the ground wire is the same size as other copper wire in the branch circuit it serves, such as #14 copper, then it might be functional.

All of this is wild guessing to this point.

On 2020-03-28 by Doug

see image

On 2020-03-27 - by (mod) -

Do you think tne ground may have been added?

Follow the ground to see how it is connected to devices and boxes.

Use the add image button.

Watch out: also see FEDERAL PACIFIC FPE HAZARDS

On 2020-03-26 by Doug

Hi, I'm helping a friend replace some outlets and fixtures, and replace a Fed. Pacific sub-panel.

The house was built in 1958 and seems to be mostly done with NM-2 with no ground.

Here's the odd thing -- in the kitchen walls, which we opened up, there is a single #14 wire going through the studs, through nicely drilled holes about 20" off the floor. I checked with a volt-meter and it goes to ground. One of the outlet boxes is tied to it.

Never seen that before. Did the original electricians put it in there in order to ground the kitchen appliances perhaps?

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

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 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.

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.

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.

See CEILING LIGHT FIXTURE INSTALLATION

...

Continue reading  at ELECTRICAL GROUNDING in OLDER HOMES or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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