Electrical question: 110 and 220 in same conduit

I need to run both a 110V and 220V line to an outdoor deck. There is an existing PVC conduit between the circuit box and the deck. Are there any concerns with running both lines through the same conduit?

I can’t think of one. Each line is insulted. Wires of different voltage are run next to each other quite often. Especially on ships.

Hard to get any respect inside a conduit.

Damn typing on phones with fat fingers.

Insulated even. .

I’m not expert enough on the NEC to offer a direct answer to the OP. We do have for-real electricians around here that can answer. I would suggest that shipboard practice may be quite different than what NEC wants.

You definitely can NOT legally run low voltage stuff like phone or data cables in the same conduit as 110v power.

It’s OK to run multiple circuits in the same conduit, but you must calculate the “wire fill” capacity based on wire sizes required.
Also, there’ really no such thing as a 220V wire - it’s two 110V on different legs, which means a minimum of 4 wires plus grounds.

I thought it was 4 wires total: red (hot), black (hot), white (neutral), green (ground).

The OPs situation will require at least 4 wires plus one ground: hot and neutral for the 120V circuit, two hots for the 240V circuit. 240V circuits don’t require neutral if the load doesn’t need it (and many don’t).

You need:
Hot and Neutral and Ground for the 110V circuit.

Hot1 and Hot2, Ground and (maybe) Neutral for the 220V circuit.

Things have changed over the years, and some appliances require 4 wires for 220V.

You only need one ground in the conduit (large enough for the larger/largest circuit). You don’t need a ground per circuit.

Thank you for all the responses, much appreciated.

So you really only need 1 line. If it is heavy enough to handle the full load, you could just take the 110 off two legs of the big one (unless, of course, if selective remote switching is an issue).

This is likely not code compliant.

Agreed.



Run 2 separate wires, but both can be in the same conduit.

If you’re putting in a sub-panel would be the exception where you could run one and then separate from there.

Though you still would need 4 wires for this sub panel, and if on land you might need to also bond to ground.

Of course and agreed.

Not in the USA, anyway. It’s the norm in Europe.

Now that the OP has been answered I have a different related question if I may.

Yes, as several have said, in North America household “220” is simply both halves of the typical split-phase power delivered from the utility feed in the street. So from a strict instantaneous-voltage-to-ground perspective it’s a distinction without a difference. So there’s no incremental hazard running them side by side in the same conduit.

But …

In industrial settings it’s not uncommon to have motors that run on, e.g. 440V 3-phase power. Inside large factory campuses you may well be distributing power from area to area in kilovolt-class lines with smaller local transformers attached to individual buildings. I’m talking big heavy-duty facilities like a shipyard, Boeing’s airplane factory, or an automobile assembly plant.

In a place like that where you do have both ordinary 110V and also materially higher voltages running around in the same building, is it allowed and/or is it normal practice to combine different voltage conductors in the same (large) conduits? Or must all that stuff be segregated?

You can, but the insulation on the wires has to be rated for the highest voltage in the conduit. In other words, if you mix 120 and 480 volt wiring in the same conduit, the insulation on both the 120 and 480 volt wires has to be rated for 600 volts.

This is correct for the Tesla Wall Connector. Only 3 wires needed H1, H2, ground