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Is it safe to have Steel Armored Cable AC-90 touching/running along steam pipe

I asked my contractor this question he has the cable running w the steam pipe in the basement and is boxing them out

Comments

  • New England SteamWorks
    New England SteamWorks Member Posts: 1,429
    edited September 2018
    Yes. But of course you should not have an uninsulated steam pipe. And if it were insulated, -double yes.
    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
    newenglandsteamworks.com
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,290
    Absolutely not. At best those wires are rated at 90 deg C (194 F). Since steam is at least 212 your overheating the wires. If the pipe is not insulated you need an air space. If boxed in and uninsulated you need a larger air space (no air movement) If the pipe is insulated in an open basement it shouldn't be a problem but avoid the issue
    ChrisJSeanBeans
  • Leonard
    Leonard Member Posts: 903
    edited September 2018
    Problem is electrical code demands you de-rate power cable amperage capability if ambient temp is over some room temp (maybe 70 or 86 degs F) .

    Most likely the electrician assumed room temp ambient when he selected wire size, put wire in a hot area and it will very like not longer meet code. Basically insulation will get hotter than it's rated for. Highest temp wire I've see is 105 deg C , and even that won't have any margin for electrical self heating that occures in wires due to IR loss. Steam will be ~ 100 deg C.
    ChrisJ
  • luketheplumber
    luketheplumber Member Posts: 134
    I would best avoid that if I were you better safe than sorry
    I just earned my GED and am looking for a apprenticeship with one of these steam gurus on this site!
  • BobC
    BobC Member Posts: 5,228
    Most home boilers really don't draw much current, maybe 3-4a steady state. Assuming it's #14 wire there is a lot of headway there but there is still the question of wire insulation degradation.

    That said it is not good practice to let BX contact steam piping unless it's well insulated. There should be an air space between the cable and an uninsulated pipe.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • BobC said:

    Most home boilers really don't draw much current, maybe 3-4a steady state. Assuming it's #14 wire there is a lot of headway there but there is still the question of wire insulation degradation.

    That said it is not good practice to let BX contact steam piping unless it's well insulated. There should be an air space between the cable and an uninsulated pipe.

    Bob

    There's air space between the armor and the wire.
    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
    newenglandsteamworks.com
  • Leonard
    Leonard Member Posts: 903
    edited September 2018
    I'ld make it feet , not few inches.
    But still prefer it not to be in a hot area.
    Code is giving this subject more attention now days.
    People used to lay HVAC power cables across a hot summer roof.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,290
    Common sense. Heat is the enemy of any wire. Wiring should be kept away from heat. If unavoidable the wire must be rated at a higher temperature than what it is subjected too or it will degrade.

    Heat comes from two sources, the heat generated in the conductor is determined by the wire size and the amperage it carries & the ambient temperature it is installed in. Both must be considered to determine the total temperature