Junction box grounding & pigtail questions

[Jim]

I'm installing a dimmer switch to replace a wall light switch (in the USA). The house was built in the 1960s and the junction box is metal and grounded. However, the ground wire from each cable (NM romex cable) entering the box is connected directly to the box (no pigtail.)

The new dimmer switch has pigtails, including the ground wire. Is it ok to connect a short green (stranded) wire to the box, and then use a wire nut to connect this to the green dimmer pigtail? (Today, normal practice is to connect the ground wire from each cable entering the box to a wirenut, then use a pigtail to ground to the box, but this is not possible with my existing wiring.)

Also, the dimmer pigtails are stranded wire. Is there a recommended way to connect solid to stranded wire in wire nuts?

Thanks!

[Takoma Park Volunteer Fire Dep]

Please tell us how the Equipment Grounding Conductors (EGCs) from each cable is connected to the box. If that was not done with a reliable method then you will need to rework the box. If in doubt you should do a ground return impedance test using a Suretest or a good meter and a dummy load such as portable hair dryer. Unless you are fully conversant with the manual test technique you can actually start a fire attempting it so don't try to wing it.

-- Tom H

[Doug Miller]

Almost. Connect a short green, or bare, *solid* wire to the box, and use a wire nut to connect it to the stranded green pigtail from the dimmer.

Not possible, or not easy? :-)

Strip about 1/8" (3mm) more insulation off of the stranded wire than off of the solid wire. Twist the strands together. Put the wires side-by-side with the cut ends of the *insulation* lined up (so that the end of the stranded wire projects about 1/8" past the end of the solid wire). Screw the wire nut on good and tight.

-- Regards, Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?