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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Jeff Lelko on October 06, 2020, 03:44:20 AM
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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 (https://www.homedepot.com/p/AlumiConn-3-Port-Al-Cu-Wire-Connectors-10-Pack-95110/202889892?MERCH=REC-_-pipsem-_-202935616-_-202889892-_-N), 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!
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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!
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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.
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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.
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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.
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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.
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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)
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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.
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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.
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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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While these are convenient, I believe they have limitations on amperage/voltage.
https://www.wago.com/us/wire-splicing-connectors/compact-splicing-connector/p/221-415
They are, as the cool kids say, 'the bee's knees'. UL rating is 600V, 20 amperes. IEC is 450V, 32 amperes. Solid or stranded, fine stranded... all on the linked page.
Jonathan's comment about box fill (wire count) is worth a re-read. Box fill (and conduit fill) is NEC 314.16.
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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.
What do you call (or part number) those hubbell boxes with the metal strain relief?
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What do you call (or part number) those hubbell boxes with the metal strain relief?
The box is a Hubbell/Bell 5341-0 (https://www.hubbell.com/bell/en/Products/Electrical-Electronic/Outdoor/Boxes-Covers-Plates/5341-0/p/1670276). A matching grey steel receptacle cover is Hubbell SP82G.
The cord grips are Hubbell 3/4" NPT. The exact ones I use depends on the OD of the cord:
Carol 12/3 SJOOW - part no. SHC1034 (https://www.hubbell.com/wiringdevice-kellems/en/Products/Electrical-Electronic/WireCableHose-Management/Cord-Connectors/SHC1034/p/1674618), F2, 1/2" to 5/8" cord OD, brown
Carol 12/3 SOOW - part no. SHC1037 (https://www.hubbell.com/wiringdevice-kellems/en/Products/Electrical-Electronic/WireCableHose-Management/Cord-Connectors/SHC1037/p/1674626), F3, 5/8" to 3/4" cord OD, yellow
The boxes were available at Home Depot, the cord grips I think I ordered from Zoro.
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A couple more pics of the build. Here I used Hubbell HBL5262 (https://www.hubbell.com/wiringdevice-kellems/en/Products/Electrical-Electronic/Wiring-Devices/Straight-Blade-Devices/Industrial-Receptacles/HBL5262/p/1636605) receptacles. At nearly $20 each, they push the price of a complete box, with a 12' cord and 6" pass-through, over $100 just in materials. People are stunned when they ask me how much I would charge to build them a few.
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The box looks like a Bell 5333-0 or 5341-0. The strain chuck is Raco 4802-4 or 4803-4 (I think). Both are Hubbell companies.
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I've seen the wire nuts
I'm sure the rest of the world looks at american wire nuts and thinks "What???!!!".
Steve.
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Thanks for all the input and suggestions.
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!
That was generally my initial thought too. I like the solid feel of the screw terminals, but also understand that they will require occasional re-tightening. What's interesting about the Wago connectors is that they actually have a vibration spec. I'm not really sure how that correlates to real world use, but it's reassuring to know the engineering team considered it during design.
Thanks for sharing the pictures of your project Paul! I use the OA Windsor rubber boxes for portable power distribution, but you did an excellent job with your build as well.
Jonathan's comment about box fill (wire count) is worth a re-read. Box fill (and conduit fill) is NEC 314.16.
I agree, and thanks Jonathan for providing all the background info. To give some further context on my end, attached is the website picture for essentially what I'm wiring - a simple PowerCon split. Since those use the spade terminals and not the screws like a 5-15 outlet I can't just simply daisy chain along the devices as I go.
I'm sure the rest of the world looks at american wire nuts and thinks "What???!!!".
I've learned as I researched this that apparently wire nuts aren't permissible in other parts of the world. Interesting to say the least!
Thanks again!
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Vibration can make a screw terminal work loose, and screws tend to not self-tighten.
Just a thought, not backed by research.
Blue Loctite is your friend for those screws that don't "self tighten" :D
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The box is a Hubbell/Bell 5341-0 (https://www.hubbell.com/bell/en/Products/Electrical-Electronic/Outdoor/Boxes-Covers-Plates/5341-0/p/1670276). A matching grey steel receptacle cover is Hubbell SP82G.
The cord grips are Hubbell 3/4" NPT. The exact ones I use depends on the OD of the cord:
Carol 12/3 SJOOW - part no. SHC1034 (https://www.hubbell.com/wiringdevice-kellems/en/Products/Electrical-Electronic/WireCableHose-Management/Cord-Connectors/SHC1034/p/1674618), F2, 1/2" to 5/8" cord OD, brown
Carol 12/3 SOOW - part no. SHC1037 (https://www.hubbell.com/wiringdevice-kellems/en/Products/Electrical-Electronic/WireCableHose-Management/Cord-Connectors/SHC1037/p/1674626), F3, 5/8" to 3/4" cord OD, yellow
The boxes were available at Home Depot, the cord grips I think I ordered from Zoro.
That's interesting and what I was after. The average price of the rubberized pendant boxes like Windsor uses from both Hubbell and Ericson is nearly twice the price. I have some of the style you are using that came from an acquisition. They have held up as well as the OA Windsor product. Interesting.
Thanks Paul
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At nearly $20 each, they push the price of a complete box, with a 12' cord and 6" pass-through, over $100 just in materials. People are stunned, and then insulted, when they ask me how much I would charge to build them a few.
Maybe a big bill, but I'd wager those boxes won't fail on you in the middle of a gig, and won't be subject to an NFG label anytime soon. Like almost anything else, you get what you pay for.
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Ideal Wing Nuts and Ilscos
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I've learned as I researched this that apparently wire nuts aren't permissible in other parts of the world. Interesting to say the least!
Probably because most of the rest of the world runs at 220-240 volts rather than 110 volts.
Steve.
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Probably because most of the rest of the world runs at 220-240 volts rather than 110 volts.
Steve.
Wire nuts in the USA are good for up to 600VAC. I am a retired commercial electrician. We used them on 277 volt lighting legs. I dont like push on connectors. I have opened J-boxes and found wires had somehow popped out of push ons.
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The pictured WAGo connectors are not push on's-they are actually a lever/cam lock. I have seen them used in higher end lighting fixtures-very nice to work with and the electrical connection is always under spring tension-meeting the code requirement for a "pressure connector"-which is essentially what wire nuts are as well. I like the fact that since there is one wire per hole yo are less likely to have a wire slip out of the connection-especially if using more than 2 or 3 wires.
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Per UL 1059 Standard for Terminal Blocks, they are rated at 600V and 20A.
Good to know. The big box stores I saw these connectors in showed their max amps at 12. I didn't see that they sold anything larger. I'm not a big box store fan, I wasn't surprised to see that was all they had. I ended up with wire-nuts for the project.
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I will second (or third/forth/fifth!) how great Wago connectors are, they are pretty much the electricians standard cable joining connector here in the UK from what I've seen online, much easier that using standard "choc-bloc" terminal strip, Wago also do special enclosures for them (for just housing the Wago connectors/wiring) to make it maintence-free for installation work.
The lever type already mentioned will take conductors from 0.5mm-6.0mm! both stranded and solid, I've used them happily on 0.75mm˛ rubber pond flex, 1.25mm˛ PVC flex and 2.5mm˛ solid T+E.
Specs here: https://www.wago.com/gb/installation-terminal-blocks-and-connectors/compact-splicing-connector/p/221-613
Another option I have used for when I needed to connect multiple cables together and didn't mind if the connection was not as easy to remove is to use a combination of standard "choc-bloc" terminal strip and insulated bootlace ferrules designed for two cables, you can connect 4 cables together easily, safely and reliably this way (bootlace ferrules being the bomb for wiring plugs and such like with stranded cable, and are mandated on all new devices in the UK with a rewireable plug).
(choc-bloc referring to this type of terminal strip in the UK https://i.ebayimg.com/images/g/w0IAAOSwA3dYVqZn/s-l300.jpg )
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Thanks again for all the input! I've ordered a pack of the Wago connectors to try out and will post back if I have any further questions!
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...the electrical connection is always under spring tension-meeting the code requirement for a "pressure connector"-which is essentially what wire nuts are as well. I like the fact that since there is one wire per hole yo are less likely to have a wire slip out of the connection-especially if using more than 2 or 3 wires.
Whenever I install a wire nut, I always tug on each wire individually to make sure it's secure. It's kind of scary how many times a wire will just pull right out, and that's probably why they're banned in some countries.
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https://www.wago.com/us/wire-splicing-connectors/compact-splicing-connector/p/221-415
They are, as the cool kids say, 'the bee's knees'. UL rating is 600V, 20 amperes. IEC is 450V, 32 amperes. Solid or stranded, fine stranded... all on the linked page.
Jonathan's comment about box fill (wire count) is worth a re-read. Box fill (and conduit fill) is NEC 314.16.
Nice! Thanks Tim.
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I've learned as I researched this that apparently wire nuts aren't permissible in other parts of the world. Interesting to say the least!
When I was doing some electrical in Mexico I would have loved to have some wire nuts. Apparently they aren't permissible there either. They just twisted the wires together (you hope at least) and wrapped it with electrical tape. I looked around in the electrical section of a few stores and not a single wire nut or other type of multi-wire connector to be had. I can't recall if there were butt splice crimps or not, probably not.