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Multiple conduits from house to garage (gas, electric, low voltage) : is there a separation rule?

mangler66 | Posted in GBA Pro Help on

I am pouring my frost walls tomorrow (London, Ontario), and I will be adding an 8″ sleeve 3′ down in both walls so I can run (3) separate 2.5″ conduits from the house to the garage (about 20′ between house and garage). Things I may be running through the conduits:

1 Natural gas
2 Electrical (to feed a 100 amp garage panel)
3 3/4″ cold water pex line (to feed garage taps and utility sinks)
4 1/2″ pex hot water line (to feed the utility sink)
5 (2) 1/2″ pex lines (supply and return) to supply the in slab heat from the main water heater
6 Low voltage lines (Cat5e, RG-6U)

As you can see, it can get crowded in there pretty quick. My main concern is will they allow me to run electrical and natural gas in the same 8″ sleeve (different conduits)? Is there a separation rule even when they are in different conduits? In walls low voltage stuff is usually 6″ away from high voltage wires, will that be an issue? I know they won’t let me run electrical and gas in the same conduit, but what about gas and low voltage (ethernet, cable)? Gas and water/radiant heat pipes? Looking for acceptablee combinations in the same 2.5″ conduit. I will run out of space quickly, especially if I want to insulate the hot water and radiant feed lines.

Any advice on the grade/thickness/certification for the 2.5″ conduit? Mostly concerned about the main electrical line.

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  1. Expert Member

    "I don't know if they will let me"

    Mai Tai, You need to start talking to the "theys". That's how the process works. Well before it becomes a rush because you want to pour, you need to understand what is required. Getting advice on these types of things on the internet is asking for trouble.

  2. GBA Editor
    Martin Holladay | | #2

    Mai Tai,
    I agree with Malcolm. You need to talk to:
    1. Your local building inspector.
    2. Your local natural gas supplier.
    3. Your electrician.
    4. A representative from your local electric utility.
    5. Your telephone company.
    6. Your plumber.
    7. Your excavation contractor.
    8. Your architect and engineer (if your project has these professionals).

  3. mangler66 | | #3

    Given the current state of the construction industry here, I'm afraid I' m on my own until the foundation is complete. I found a well written guide for Puget Sound utility in Cali that highlights separation between gas, electrical and TV/ phone. They mandate 12" horizontal separation in the same trench( with or without conduit, which is odd). I ended up using (3) 3 in sleeves, 18 inches apart. This should cover any Canadian safety factor.

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