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[Jeff Lelko]

Greetings, I'm curious to hear what everyone's preferred method is for wiring basic junctions.  This is along the lines of simple distribution in a junction box.  I've seen the wire nuts, Wago 221s, push-connectors, insulated screw terminals such as this, and a few other solutions.  What's the general consensus as to what's "best" for portable power distribution where daisy chaining the screw terminals on the outlets isn't an option?  Circuits are 120v 20A.  Thanks!

[Keith Broughton]

In portable power distribution, movement can be more problematic than in a fixed install like a house.
I try to use connectors with screws rather than wire nuts or any kind of "push in" connector.
Those ones from HD look perfect!

[Paul Miller]

I love the Wago connectors for being so easy to use and laying flat in a quad box. To me they seem as secure as any screw terminal.

[Jonathan Johnson]

I love the Wago connectors for being so easy to use and laying flat in a quad box. To me they seem as secure as any screw terminal.

Are the push-in connectors listed for stranded wire? I believe the push-in "backwire" terminals built into receptacles and switches are only listed for solid wire.

[Jonathan Johnson]

In portable power distribution, movement can be more problematic than in a fixed install like a house.
I try to use connectors with screws rather than wire nuts or any kind of "push in" connector.
Those ones from HD look perfect!

I would think that a push-in or wire nut (which keeps spring pressure) would be preferred, as the pressure would remain constant with vibration. Vibration can make a screw terminal work loose, and screws tend to not self-tighten.

Just a thought, not backed by research.

[Paul Miller]

Are the push-in connectors listed for stranded wire?

Yes, they are UL listed for solid and stranded wire from 24 up to 12 ga.

[Rob Spence]

But are they NEC approved?

I realize that portable wiring is different than residential but last I looked at the code, it required crimps on twisted connections for safety grounds. No wire nuts.

That said, these Wago lever lock connectors look like a great replacement for 3 to 5 wires in a wire nut (which is timely for me as I need to distribute a feed to 4 devices in a 6 gang box at home soon)

[Jonathan Johnson]

But are they NEC approved?

I realize that portable wiring is different than residential but last I looked at the code, it required crimps on twisted connections for safety grounds. No wire nuts.

I don't read that crimp connectors are required, but rather, that wire nuts are acceptable on the equipment grounding conductor (EGC). The paragraph often cited is:

Equipment grounding conductors must terminate in a manner such that the disconnection or the removal of a receptacle, luminaire, or other device won't interrupt the grounding continuity [250.148(B)].

I think there is a matter of interpretation here: I believe the intent of this clause is that the EGC would not pass through a device which, if removed, would break the grounding connection (as happens when the hot and grounded [neutral] current-carrying conductors are connected to the pass-thru terminals of a typical receptacle). So using a wire nut and a jumper does not violate the language of this paragraph.

Some electricians and inspectors have interpreted this paragraph to imply that the EGC must be connected with a non-removable connector such as a crimp ring. But a properly installed jumper from the wire nut to the device won't interrupt the grounding continuity when the device is removed.

If the EGC to the device is through a wire permanently attached to the device (such as a light fixture), then it would be necessary to use two wire nuts: one wire nut that connects the circuit EGC, the EGC to the metal box, and a jumper to a second wire nut that connects to the device EGC wire. When removing the device, you remove the second wire nut without disturbing the first. The grounding continuity in the circuit is not interrupted.

And, for what it's worth, my interpretation is that the NEC doesn't "approve" devices; rather it requires devices that are "listed" by a recognized testing authority. So if it's UL listed, then according to the Code, it's suitable according to the purpose under which the device is listed by UL.

What I love about the NEC is that it is performance-based rather than product-based. As long as the product or method meets performance criteria and is found to be safe and suitable for a given purpose by a recognized authority, it's permissible.

P.S. -- All those jumpers and ground wires and wire nuts can quickly fill a box to its wire fill capacity. Be cognizant of that; you might have to spec bigger boxes than you think.

[Bob Faulkner]

Yes, they are UL listed for solid and stranded wire from 24 up to 12 ga.

While these are convenient, I believe they have limitations on amperage/voltage.

[Paul Miller]

I believe they have limitations on amperage/voltage.

Per UL 1059 Standard for Terminal Blocks, they are rated at 600V and 20A.

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