Terminating stranded wires

NO!

RE

It won't pass UL/CSA/VDE or any other code. Terminate the wire by crimping/soldering it to a terminal such as a spade or ring connector then put that to the screw of the device.

That would be surprising to U/L. Reading from the U/L white book ... Receptacles For Attachment Plugs and Plugs (RTRT) "Terminals for the wire-binding screw, setscrew, or screw actuated backwiring clamping types are suitable for use with both solid and stranded building wire." Thus it is also OK with the National Electrical Code.

Where do people come up with these urban legends about things that are "illegal"?

You just confirmed what I said. USE TERMINALS. Nowhere does it say in any code, including NEC that its okay to simply wrap a wire around a screw. In ALL cases it specifically mentions using a terminal.

"Terminal" in electric code language is anywhere a wire terminates. I assure you they don't mean a crimped/soldered "ring/spade" terminal.

How would you shove one of them in a backwire clamp?

No sir, you're misinterpreting what the quote you sited says. A terminal is a specific piece of hardware. There are screws that are integrated with wire terminals and there are many types but there is a distinct difference between something that is a terminal, and something that has been terminated. Example: The wire is terminated to a terminal. Terminated is to end something. Terminal is what you terminate something to. In the quote you sited below..........

A wire binding screw is a terminal. It is not used for assembling devices, which is what the OP was asking...."Is it ok to terminate stranded wire around the screws of a device?" Note the pictures at the URL listed below. These are terminals that utilize a screw as part of the terminal structure however they are specifically designated as terminals in this case board mounted and are absolutely not used for construction of the device itself.

Setscrews, clamping screws, etc are also terminals that utilize a screw as part of the terminal, to make the termination of a wire. As in barrier strips, the screw clamps the wire to the terminal, but the wire is at no time simply wrapped around the screw threads. The closest you might get to that is with the screw actuated backwire clamp, but note the wire is clamped between two plates, not wrapped around the screw threads The UL reasoning for this is that the threads of a screw are sharp enough and there is enough tension, to cut into the wire thus making it unsafe should the wire be cut through.

One of the better sites with explanations and pictures to demonstrate, is

The OP asked about the screws of a device, meaning the screws that are used to hold the device together. IF the device screw is one of these types of terminals, then sure, he can use it to terminate his wire, but in answer to his direct question.... no, it is never okay to terminate a wire AROUND the screws of a device.

Your quote is excellent, and points specifically to the use of terminals.

No sir, he is not. It is as he said. To verify this for yourself, disassemble a UL listed floor or table lamp. The stranded lamp cord terminates at the socket terminals, and the stranded conductors are wrapped around the screws there with no ring/spade/whatever connectors.

Well, I have three of those, and each are terminated to a wire binding screw, which is a terminal, not a device screw. That little tab of metal that is upturned, is to prevent wires from spreading/slipping out from under the screw head. It's still a terminal.

In the rare case that I wrap a wire around a screw, I usually strip the wire extra long, tin it and wrap it clockwise. Consumer devices such as lamps are a good example of when this might occur. The only problem with tinning a wire is you need to go back later and re-tighten the connection. Since tin-lead is soft, just like the aluminum wire put into homes many years ago and has a tendency to create bad connections.... My two cents...Ross

EEng is right. If the rest of you would open and read UL's White Book then you would know for yourself. Reading the NEC does not give you a license to dispense unfounded advice.

Well, I have three of those, and each are terminated to a wire binding screw, which is a terminal, not a device screw. That little tab of metal that is upturned, is to prevent wires from spreading/slipping out from under the screw head. It's still a terminal.

The *only* thing I do this with is speaker cable. 16AWG zipcord, stripped, looped, and tinned. Of course if I were a true audiophool, worried about the "purity" of the high frequencies, I'd have used silver solder.

I'll see that and raise you two. I assume it's three raises and table-stakes here.

No limit

I see that Greg, you and seem to be in agreement. Stranded wire can be wrapped around a screw. The UL white book does not prohibit such a connection. The screw must be part of one of the device's terminals. The difference is that you want the more complete description "terminal screw" (which I see as obvious by the question). Do I properly understand you?

Funny you should say that....That's how I prepared the wires on my speakers binding posts!....Ross

Sheesh I've never seen anyone fight so hard to be wrong. A screw actuated terminal is one in which the screw is used to hold the wire in place against a constraint that prevents slippage such as a clamp, an upturned tab, etc. A mere screw used in the assembly of an enclosure is none of these and cannot be used to terminate a wire merely by wrapping it around the threads of said screw. UL is very specific about using the terminology TERMINAL. If it had meant screw by itself, it would have said screw by itself.

I assume we are talking about a barrier strip??? Just curious...... :>)

You don't use Litz wire? ;-)

It is very clear nobody here who thinks a "terminal" is anything other than the screw on the side of a device has never worked in a commercial electrical project where they pull a lot of stranded wire through raceway systems. I suppose the hundreds of buildings I have inspected are ALL wrong but it would be a huge surprise the the electricians and other inspectors who work there. The trick is simply craftsmanship. You tightly twist the wire and properly tighten the screw. If you want to crimp on a spade terminal with the correct tool and use that or tin the wire, by all means do so but you will never see either of them on a commercial wireman's tool cart.

Fine, believe what you want. If you can't distinguish between a proper terminal and a device screw then more's the pity, and just because it is common practice to save money and time by using a standard screw AS a terminal when it is clearly not, neither by design or by code, doesn't make it right. Between the political BS and bottom line dollar, more is done incorrectly on purpose, with authorization than is done by the book. Clearly, those who believe that a device screw is a terminal, have never worked on anything DOD.

End of topic out of sheer frustration with those who demand the right to do it wrong.