#10 - #12 AWG Stranded Wire?
#10 - #12 AWG Stranded Wire?
(OP)
NEC requires most conductors #8 AWG & larger to be stranded. For #10 & #12, stranded or solid can be used.
However, I've never seen stranded used for #10 & #12 (only one exception ever to this). #10 & #12 are almost ALWAYS solid.
I understand that there's essentially no cost difference between stranded and solid.
So -- how come stranded wiring is not used more often for #10 & #12 wiring?
However, I've never seen stranded used for #10 & #12 (only one exception ever to this). #10 & #12 are almost ALWAYS solid.
I understand that there's essentially no cost difference between stranded and solid.
So -- how come stranded wiring is not used more often for #10 & #12 wiring?






RE: #10 - #12 AWG Stranded Wire?
Mike
RE: #10 - #12 AWG Stranded Wire?
RE: #10 - #12 AWG Stranded Wire?
RE: #10 - #12 AWG Stranded Wire?
RE: #10 - #12 AWG Stranded Wire?
The primary advantage of solid is that you only have 1 strand to clean with #220 silicon carbide abrasive paper as recommended by the Consumer Product Safety Commission which is a variation of the old Signal Corps method. The reason why you see electrical systems from WW 2 is that there was not enough copper to go around, therefore you had to have ALL the wire strands conducting. For more information go to Dr. Jesse Aronstein's website www.inspect-ny.com
RE: #10 - #12 AWG Stranded Wire?
The twist-on "wire-nuts" used for fixture and receptacle wiring work well with solid wire and generally solid wire will be less expensive.
RE: #10 - #12 AWG Stranded Wire?
Electrically, there is little difference in power circuits. I know that control panel builders prefer stranded for it's ease of training and lacing and it's flexibility.
RE: #10 - #12 AWG Stranded Wire?
From your viewpoint you never see stranded being used, so I assume that you are primarilly referring to lights and receptacle wiring for the reasons mentioned above.
For those of us in the industrial world, it would be almost the opposite. We RARELY see solid wire being used for anything other than signal wires and low voltage systems (under 50V) like alarms or instrumentation where it is 18ga and smaller. Industrial common practice precludes the use of "wire nuts", favoring terminal blocks or crimp-on pressure connections that do not work well with solid conductors.
"Venditori de oleum-vipera non vigere excordis populi"
RE: #10 - #12 AWG Stranded Wire?
mc5w,
I've never seen copper conductors cleaned with silicon carbide abrasive paper unless the conductor has corrosion damage. The CPSC website information pertains to the use of aluminum conductors, not copper.
Don
RE: #10 - #12 AWG Stranded Wire?
Resqcapt19, Dr. Jesse Aronstein says that my grandfather ( who was ex-Signal Corps ) trained me well and that it is appropriate to clean copper wires with silicon carbide paper when new. Thanks to catalytic converters copper wiring that is outside burns up just as fast as aluminum unless both metals are cleaned and treated with joint compound. If you read his directions you have to clean both the copper wire AND the aluminum wire when connecting the two together.
Dr. Aronstein also ran some different tests of copper to copper connections as well as copper to aluminum and aluminum to aluminum. In all cases the wires that were not cleaned with silicon carbide paper or diagonal cutters burned up well before the ones that were cleaned. That is, the Old Signal Corps method plus electrical joint compound is the best method and cleaning the wires but not applying joint compound is second best but still vastly superior to not cleaning the wires.
He also ran some tests that showed that "cleaning" aluminum or copper wire with a wire brush is completely ineffective.
I am facing the task of replacing 18 compact fluorescent lampholder that are 2 years outdoors in November weather. The reason why is that the manufacturer never bothered to clean the #18 solid copper wire and apply Ilsco Deox(R) to prevent corrosion. The fixtures face Woodland Avenue ( a main drag ) in Cleveland, Ohio.
A year ago an indoor system started having problems with failures in solid #12 copper wire that was 27 years old because the installers never bothered to clean the wires like old timers did. This was an ordinary indoor environment. The reason why you see 60 year old electrical systems that are still going strong is that the old timers had to have ALL the wire strand conducting because there was not enough copper to go around. You could not substitute 750 KCM for 500 KCM because only 2/3 of the wire strands were conducting.
RE: #10 - #12 AWG Stranded Wire?
I've never seen a manufacturer's instruction or a design spec that required copper conductors to be cleaned prior to termination. Is this a commom practice?
Don
RE: #10 - #12 AWG Stranded Wire?
Copper/copper splices generally do not require such cleaning.
mc5w please correct me if I've misunderstood.
Aluminum wiring ALWAYS requires such cleaning as it Al oxidizes nearly instantly upon contact with air; the resulting oxide is essentially a non-crystalline sapphire, which is highly resistive. These high-resistance splices are the cause of fires associated with aluminum wiring. To prevent the fires, aluminum MUST be sanded AND coated with an anti-oxidant joint compound. Aluminum/copper splices MUST be made with listed ALCU connectors. Nothing new here, this was all recognized some 20 years ago.
RE: #10 - #12 AWG Stranded Wire?
Installation Recommendations for Bronze and Copper Connectors:
Bronze Bolted Connectors - Contact sealants are not normally required in copper connections. However, the use of sealant is recommended in severe corrosive environments and direct burial applications such as ground grids.
Vigorously clean the conductor and connector contact surfaces with a stainless steel wire brush.
Alternately and evenly tighten bolts with a torque wrench to the values shown in Recommended Torque Values table.
RE: #10 - #12 AWG Stranded Wire?
What you are refering to is valid for larger cables that would use bronze connectors such as those made by Anderson. Look however at the topic of the post. We are talking about #10 and #12 wire, not cable.
"Venditori de oleum-vipera non vigere excordis populi"
RE: #10 - #12 AWG Stranded Wire?
The CPSC site states that the failure of aluminum wiring used in the 60s and 70s was due to "... the differing thermal and mechanical properties of aluminum and the metals used in outlet contacts."