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carbon steel screw versus brass screws

Discussion in 'General Electronics Discussion' started by spaceman, Nov 30, 2016.

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  1. spaceman


    Nov 5, 2016
    I am doing some home wiring and using salvaged light switches, outlets and such. Some are missing the brass screws used to keep the wires connected to to the contacts. I priced out new brass screws at 28 cents. So I looked at some carbon steel screws same length and thread for 8 cents apiece. I am on a tight budget. Is there any reason not using the steel versus the brass? I know aluminum is a big no no , but I am not working with aluminum wire, just copper.
    I assume the screws were removed from the outlets for the scrap metal worth of brass.
  2. duke37


    Jan 9, 2011
    I would worry about corrosion in damp conditions such as kitchens or external walls.
  3. oz93666


    Dec 7, 2014
    Brass is about 3 times more conductive of electricity than steel , that will cause more heating of the contact area if steel screws are used ... also there is the difference in thermal expansion , if you use steel screws this could loosen the screws over time...

    I'm sure if manufacturers could get away with using steel screws they would have done so... I would use brass screws.

    I doubt anyone salvaged the screws for scrap , not worth it , probably just unscrewed them to free the wire , and they fell to the floor.
  4. shrtrnd


    Jan 15, 2010
    My guess is, as duke37 noted, brass screws are more desirable because they don't corrode. That's my guess as
    to why whomever you got the switches from are missing the brass screws. They were salvaged because whomever took them wanted them for his own use in something else.
    In my younger days I started out as a residential electrician. At that time aluminum wire was coming into use because
    it's cheaper than copper wire.. The problem that my boss explained to me, was that the service entrance buss bars were still copper. Mating the
    aluminum wire to the copper buss bars somehow caused (with connections that weren't tight), the aluminum wire to vibrate with the 60Hz on the power line, resulting in a fire. I don't know how accurate that explanation was, but I
    do know we accidentally burned down a few houses back them because to the aluminum/copper connections at the service entrance.
    Nobody ever explained to me why, but like you, I noticed on the outlet and switches themselves, one steel screw, and one brass screw. I ASSUMED they did that so you would know to wire the neutral to the steel screw, and the hot wire to the brass screw, just so the entire house would be consistent. All the neutral wires to steel, and all the hot wires to brass. Once again, I just assumed that, and somebody here might have a technically more accurate
    Because of the return of mostly copper wire, I don't THINK it matters if you replace the missing brass screws with
    steel ones, they've always used steel on the outlets and switch neutral wires. I can't think of a reason why they both couldn't be steel. UNLESS there is actually an electrical code that specifies brass be used for hot wires. Call an
    electrical supply store and ask about those screws.
    I will mention however, if the electrical supply store says steel for both is ok, that you should take care to ensure that, for safety sake, you consistently wire all of the outlet connections exactly the same. All the polarized plug neutrals to the white wire, and all of the hot sides of the outlets to the black wires. (Which is why I THINK they used steel and brass screws, to identify one from the other).
    That's my 2-cents worth.
  5. phin


    Mar 29, 2016
    I do not think the "shiny" screws are plain steel. I am quite confident that plain steel would react to the copper. It may not fail, but then again, it may. I am guessing that the shiny ones are nickle plated to avoid this issue.

    I do wonder if a trip to a big box retailer may get you the right screws to put in your switches. They would not have to be color coded to get the job done.

    From what I remember, the two colors have real meaning on an outlet, as it has both hot and neutral. On a switch, there is no neutral, as you only switch the hot side of a circuit in most cases. This means the difference in color on a switch carries little meaning.
  6. BobK


    Jan 5, 2010
    Hmmm. Looking at Lowes website, you can get a brand new outlet complete with 4 screws for 48 cents. Even at 8 cents per screw, salavaing seems pretty silly.

  7. spaceman


    Nov 5, 2016
    What makes me look silly is paying for 2 gallons of gas to get to Lowe's to get that outlet. You did not think this one through and are in error.:p
  8. Fish4Fun

    Fish4Fun So long, and Thanks for all the Fish!

    Aug 27, 2013

    I think there is A LOT of over-thinking going into this... LoL! The **new outlets** I have on hand have 2 * "Gold Colored" screws on the "line" side and 2 * "Silver Colored" screws on the "Neutral Side" and a single "Green Colored" screw for the ground connection ..... The "color" of the screws is NOT indicative of the base material, which is certainly a ferrous alloy (confirmed with a permanent magnet). The "color" of the screws (in the US) is to conform with electrical codes in an effort to ensure outlets are properly wired. I cannot imagine that the "Gold Colored" plating on the "line" side screws significantly alters the impedance of a completed circuit .... If it did, I would expect to see similarly plated screws in panel boxes and breakers ;-)

    All of that being said, I would purchase **new** outlets rather than purchasing replacement screws for "salvaged" outlets based solely on the risk/reward ratio .... Assuming common hardware grade screws cost $0.08 each and 5 are required for each salvaged outlet, this suggests a cost of $0.40 per salvaged outlet .... locally I can purchase new outlets (in quantity) for ~$0.38 each .... Without knowing the providence of the Salvaged outlets, I would not be willing to pay more to repair them than the price of new outlets .... If there are a sufficiently large number of salvaged outlets with **some screws** remaining, you might consider using the screws from 2 or 3 salvaged outlets to make 1 "complete" outlet in an effort to save $0.38, but even that seems a bit of a stretch ... :)

    Harald Kapp likes this.
  9. shrtrnd


    Jan 15, 2010
    Interesting reading here. One thing I did think of that you might check if you re-use the old sockets:
    One house I was in, the sockets were so old that when you plugged a cord into the socket, the plug
    often just fell out of the outlet. The spring steel in the sockets had weakened, and the plug was loose
    in the socket. If you reuse those sockets, you might want to plug a cord into each socket, just to be
    sure the plug is held tightly in place.
  10. JWHassler


    Dec 22, 2014
    So buy enough of them to make it worth the gas.
    These things are going to be hidden in walls surrounding your family and that's no place for for false economy.
    davenn likes this.
  11. davenn

    davenn Moderator

    Sep 5, 2009
    well said
    and with that the thread is closed
    there has been lots of solid advice given
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