I'm in Colorado with old detached garage. Need to Run (at least) 30A 240V line to power a single EV car charger. Code says only only 1 underground conduit to garage which I already have with lots of wires (pretty packed in there) . One is dedicated to a 30A 120V Receptacle I never have used (I think it was for RV charging). How do I figure if that wire (hot, cold and ground) can be switched at the main house (200A) panel and then used for a new 240v charger in the garage? Thanks.
240V to garage using current 120V conduit
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ForceFed70
Well-known member
It can be used. You'll likely need to relabel/color one of the wires. Does your EV charger circuit require a neutral? Won't work if that's the case.
Code isn't one conduit, it's one feed, you can't have multiple circuits going to a detached structure. You may be able to pull all of the wires out of the conduit and pull 4 new ones that can power a subpanel that can power your 120v plugs and provide 240v for a charger. What size and type of materiel is the conduit?
Not sure. The 240V plug in charger that came with car says it can be plugged into a NEMA 6-20 receptacle. I'll have to research if I can purchase a wall charger that does not require neutral. I'll open up and look at the current 120v 30A RV charger receptacle -- I figured there was a neutral in there (Has thick Romex running into it). Although I had never used that receptacle it has a circular shape which I thought meant it was a 240v dryer receptacle--bummed to discover it is only a funky 120V!
Nema 6-20 is 20 amp, 240 volt. no neutral .
lakeroadster
Well-known member
To correctly answer your question we need more information.
- What's run through the conduit: wire type, number of wires and gauge?
- What amperage are you wanting to run from the house to the outbuilding?
- What distance is the outbuilding panel from the house panel?
Brewchief: It is a metal conduit that leaves my 100yr old brick house then dives underground for about 25ft and comes into my garage underground as metal. Maybe 3/4 inch. Yes, if I can't just use that 30A circuit then I think your idea will be the way to do it. Problem is I do have control over some of the lights (illuminating garden from exterior garage wall), and power in the garage from switches in my kitchen. I believe I got at least 4 separate circuits running through that little conduit. Plus, Gotta get permission from wife to eliminate those kitchen switches.
pattenp
Well-known member
If the power for those switches in the kitchen come from the garage then they are switch loops and are okay coming from the garage to the house and don't count as feeders. This only applies if there is a disconnect/subpanel in the garage controlling the power to those switches. Another thing is it sounds like the conduit is overfilled.
So I have decided to use the (current) old 3/4 in metal conduit that already runs from house to detached garage. I will pull out all the old wires and just run 6-6-6 copper THWN and #10 green for ground which will not overfill the conduit according to the chart I found. This will service a new 60Amp sub panel. (Good idea Brewchief!) Question: I have no idea how deep the 3/4 metal buried conduit runs between garage and house (25 ft). It runs under garden and then brick patio. Do I have to prove to inspector that it is 18inch deep?
alfredeneuman
Well-known member
Rigid metal conduit has a minimum burial depth of 6", not 18" (except running beneath a residential driveway or parking area)
It has a tendency to rust underground over time (even though it's galvanized).
I'd suggest you tug on the wires (turn the circuits off first) to see if their even capable of being pulled out before going any further with your plans
It has a tendency to rust underground over time (even though it's galvanized).
I'd suggest you tug on the wires (turn the circuits off first) to see if their even capable of being pulled out before going any further with your plans
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bigb56
Well-known member
If you dig away the dirt where the conduit goes into the earth, that is the point where the worst deterioration will usually show from the combination of water and oxygen greatest at that point. Often we find after 15 or 20 years there is nothing left but a pile of rust. That's if they even used RMC or IMC. Have seen people use EMT underground too. It will last a year or two. More recently installed RMC/IMC should be wrapped but only time will tell what good that does. my thoughts are that the pipe wrap will hold the condensation in.
zmaxmotorsports
Well-known member
3/4" emt is an awfully small piece of pipe to feed a service on a good day,20 years of rust doesn't help the situation.
ard
Well-known member
I see pain in your future....
Before running anything I would stop and see what is on the downstream end.
Is there ANYTHING else on that dedicated 30amp 110 outlet? If you are 110% certain beyond a reasonable doubt that it is a rune run from the inside panel to that outlet then is can be re purposed. If there is other stuff on that same circuit I would back trace and remove anything 110V on that circuit to make it a home run.
Your NEMA 6-20 outlet is a 3 wire style: two hot legs and a ground. Confirm the gauge wire used in the run, and if 12-2 or larger (and I will again stress that there is NOTHING else 110V on that circuit) WITH A FULL SIZED GROUND you can convert to 220V by wiring the white and black into the two legs of a 220V breaker, leaving the ground wire on your grounding buss in the main panel.
The wire does not give a rats *** if it is running 110V or 220V - it only cares about the current drawn (amps). There is a near 0% chance that you you will be able to pull more than 1 wire run through a 3/4" EMT over any length, so if you have to re-wire I would plan on burying new conduit of a more suitable size.
In your situation, I would try like hell to make a dedicated 220V circuit out of what is already there rather than pull new wires. You would need some sort of divine intervention to run new stuff through what is already existing.
Is there ANYTHING else on that dedicated 30amp 110 outlet? If you are 110% certain beyond a reasonable doubt that it is a rune run from the inside panel to that outlet then is can be re purposed. If there is other stuff on that same circuit I would back trace and remove anything 110V on that circuit to make it a home run.
Your NEMA 6-20 outlet is a 3 wire style: two hot legs and a ground. Confirm the gauge wire used in the run, and if 12-2 or larger (and I will again stress that there is NOTHING else 110V on that circuit) WITH A FULL SIZED GROUND you can convert to 220V by wiring the white and black into the two legs of a 220V breaker, leaving the ground wire on your grounding buss in the main panel.
The wire does not give a rats *** if it is running 110V or 220V - it only cares about the current drawn (amps). There is a near 0% chance that you you will be able to pull more than 1 wire run through a 3/4" EMT over any length, so if you have to re-wire I would plan on burying new conduit of a more suitable size.
In your situation, I would try like hell to make a dedicated 220V circuit out of what is already there rather than pull new wires. You would need some sort of divine intervention to run new stuff through what is already existing.
alfredeneuman
Well-known member
It's against all Electrical Codes, when using conduit, to hook a white wire up to a breaker.
(#4 or larger excepted, but it must be permanently marked)
Cable is a different story, although you have permanently mark it with a color (other than green) also.
We don't know what type of conduit is in though, but it's doubtful that it's EMT
(#4 or larger excepted, but it must be permanently marked)
Cable is a different story, although you have permanently mark it with a color (other than green) also.
We don't know what type of conduit is in though, but it's doubtful that it's EMT
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teamextreme
Well-known member
If it is EMT, and run underground, I can guarantee there's nothing left of it.
wyliesdiesels
Well-known member
NM type wire is not permitted underground. The wire is most likely individual conductors and as pointed out above, code prohibits re-taping of white insulated conductor smaller than #4.
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It worked out well. I hired an electrician. Removed the funky RV 30 Amp 125 V and used those 10 g wires for new 220 V NEMA 6-20. He did specifically confirm by tracing those 10g wires back the the house external main panel where he put in 2 appropriate 20A circuit breakers (can upgrade to 30 amp later if needed) . Did not have to pull any wires. No digging. Also redid all the funky wiring in garage to code. $800 total. He is a Master electrician and reports it was all done to code. Well worth it. Thanks everybody
If you have any other circuits going out to the garage it is not to code, only 1 circuit is permitted to a outbuilding.
bigb56
Well-known member
In addition to what Norcal said using the white #10 wire in the conduit for a hot conductor is also a violation, and using two single pole circuit breakers for a 240 volt load is yet another violation.
lakeroadster
Well-known member
I'd bet that the OP thinks it's 2 breakers... when in actuality it's a 240V breaker.
The #10 white wire... can't it be taped on the ends and meet code?
wyliesdiesels
Well-known member
Code does not allow rephasing of conductors smaller than #4...
lakeroadster
Well-known member
So from a function standpoint it will work just fine... but it doesn't meet code.
bigb56
Well-known member
If it were a cable assembly yes, but individual conductors in conduit it is not allowed simply because the proper colors are commonly available up to AWG-6.