How should I run power to devices mounted on posts or plywood backers in my basement? [duplicate]

Question

My home (Long Island NY) was built in 1903 and has tube and knob, Bx, cable… it’s a mess. Not easily rewired as it’s 3 stories, 6000 sq ft and I’d literally have to open all the walls and ceilings.

The basement has a few old walls (some cut starting at approx. 3 ft up due to old water damage) but is very unfinished and very industrial. Cement floor, different floor heights, HVAC duct running everywhere. Think NYC apartment building basement and you’ll have a good visual.

There are a few “wall mounted” receptacles and switches. By wall mounted they are either on a post (4x4 support) or on a piece of 3/4" plywood nailed to the brick or block. There are two mounted to the twinned furnaces, and one in the boiler room mounted on a wall made of wood planks.

What is the proper way to wire these switches and receptacles, assuming the feed is from cable at the ceiling? Is it proper as described? Or should there be conduit from the box at the ceiling to the switch or receptacle? If conduit, can it be plastic? If yes, can I use cable or will that create a double insulation issue (and therefore needs to be individual wires)? If individual wires - in a pinch - can I strip cable?

Answer 1

There are general rules based on the NEC, and then there are specific rules from the local jurisdiction. This is particularly the case in or near large cities such as New York City and Chicago. The rules can be city, county or state. For example, a quick Google search found rules for the Village of Massapequa Park, NY on Long Island which include:

• Minimum 12 AWG everywhere
• A window air conditioning circuit in every room with a window. Sounds crazy to me, as central HVAC is generally much better. But I suspect this rule came out of too many fires and problems with overloaded circuits when people started putting window air conditioning units in every room.
• No aluminum wire at all except service entrance cable (that's even stricter than Montgomery County, MD)
• Romex and plastic conduit not allowed in commercial buildings. In residential it is presumably allowed by default, but keep in mind that in at least some parts of New York City, Romex is not allowed at all. And if a building has dual purpose (e.g., apartments above retail/offices) or possibly if it is on a commercial block even if it has been converted to a single family home, then it will likely be considered commercial.

So it definitely pays to check first with your local city/county/state to make sure you do things right.

So on to your specific question, but keeping in mind that what works in most of the country may be absolutely invalid in your area:

What is the proper way to wire these switches and receptacles, assuming the feed is from romex at the ceiling? Is it proper as described? Or - should there be conduit from the box at the ceiling to the switch or receptacle?

Generally speaking, the cable needs to be physically protected from damage. That can be inside suitably large conduit (generally that means metal or PVC) or it can be by securing wood to block direct access to the cable up to 8' above the floor.

If conduit - can it be plastic - and if yes, can I use romex or will that create a double insulation issue (and therefore needs to be individual wires)?

The extra insulation is a non-issue. The issue is conduit fill - a cable fills a conduit a lot faster than the equivalent individual wires.

If individual wires - in a pinch - can I strip romex?

No. You can strip Romex for use inside junction boxes - e.g., to make pigtails. But you can't use it that way in conduit.