Can I get 220 with this existing wiring?

[GreenEnvy22]

Hi all,
I have a detached garage, built in the 1970's. There is a conduit running from the house to garage with a 3 wire (red, black, white), armored power cable. This goes under our concrete porch so no easy access to it.

Our house still has fuses, not breakers (it's on the todo list), 100 amp service.
The garage has the incoming line come into a cutoff switch, then goes to a breaker box with 3 x 15amp circuits.
Inside the cutoff switch, the black and white wires are connected to the breaker box, but the red coming from the house is just taped over, same with the red coming down from the breaker box, so they are not hooked up.

The main panel in the house, there is a double fuse going to the garage, top left in the photo. Only the top of those two has a fuse in it (30amp), so the red wire isn't powered currently at all.

I brew beer and would like to get away from using a propane burner. It's preferable to use a single 220v 4500w heating element for this, rather than two 1500w.

So a couple questions.

1-If I were to put a fuse in that empty spot in the main house panel, I take it that would be 120V from the other pole?
2-Would I then have 220v at the cutoff panel available, between the red and black wires?
3-Could I add another subpanel coming from that cutoff switch that would provide 220v, and the existing 120v would keep working?

If no to the above, then can I at least then wire up that red wire in the cutoff switch to the red wire going up to the garage breaker panel, and have it feed those 3 empty spots in the panel?

Either way I want/need the circuits to be GFCI.

There generally isn't a lot of load in the garage, just a fridge and freezer. I occasionally do run power tools like miter saws and a small compressor, but wouldn't be running those at the same time I'm making beer.

Also I know it's currently a little silly with a 30amp fuse on the house end, and that little 15amp resettable fuse in the garage. I don't know the rating of the wire itself. so haven't switched that to a 30amp.

Is it a problem there is no ground wire coming from the house?

See attached photos.

Thanks for any input.

 

[Bretny]

The short awnser is no you can't get 120/240v with only 3 wires.

 

[klassenl]

The short awnser is no you can't get 120/240v with only 3 wires.

Technically you can. But there are questions about grounding that can't be ignored.

 

[The Cobbler]

you say armoured cable in conduit, is it steel conduit? it sounds to me that you might have old BX that had a ground strap inside, it was folded over onto itself and clamped at the connector .
I'm not aware of armoured cable made without a ground.

 

[bamawildcat]

Needs 4 wires. Is the conduit you talk of just a sleeve under the concrete? I don't understand no easy access. If you have a conduit, use the previous wire as a pull string to bring new 4 wires in.

 

[wyliesdiesels]

The short awnser is no you can't get 120/240v with only 3 wires.

actually one can do so, especially on a grandfather pre-2008 system like what the OP has. The issue is the equipment grounding conductor and neutral bonding.

 

[Bert_]

First make sure you have #10 wire.

If you hook up the red wire you will have 240 and be no worse than it is now. It won't suddenly become a safety hazard. If you were installing new panels then the wire should be replaced.

Since the garage is only fed with 30a you won't have a lot of power left over. 4500 watts is 18 or 19 amps, enough left for some lights in a few things.

That's a pretty nice fuse panel in the house. Not the sort of thing I'd be in a huge rush to replace.

 

[teamextreme]

Agree with Bert. There is an unconnected red wire that when connected will provide 240v. While this won't be current code-compliant since it's missing the 4th (ground) wire, but like Wylies stated, it was legal when it was installed (provided there are no parallel metallic pathways).

 

[sberry]

When you use 3 it has to have N bonded to G in the second panel.

 

[GreenEnvy22]

Sounds like my best solution would be to replace the existing wire with some 10/3 (will have to see if I can pull the existing armored cable out and use it to pull the new wire), then replace that QO load center with a subpanel that I can run both 110 and 220V branches from?

Or do I even need the ground wire from the house if there is a grounding rod in the garage?

 

[sberry]

Yes, you need 4 wire for a new installation.

 

[jbowen]

hi guys, first time poster here. if youre going through the trouble to run a new cable, you may as well put in as big as will fit even if amperage is limited. you may end up with a larger panel inside at some point anyway, you could then up the breaker and sub-panel.

 

[wyliesdiesels]

Sounds like my best solution would be to replace the existing wire with some 10/3 (will have to see if I can pull the existing armored cable out and use it to pull the new wire), then replace that QO load center with a subpanel that I can run both 110 and 220V branches from?

Or do I even need the ground wire from the house if there is a grounding rod in the garage?

Read post #3 on he electrical FAQs sticky.

An equipment grounding conductor and a grounding electrode are NOT the same. You need both.

 

[yatg]

There is a conduit running from the house to garage

If its a metal conduit all the way, that can be your ground.

 

[exranger06]

Sounds like my best solution would be to replace the existing wire with some 10/3 (will have to see if I can pull the existing armored cable out and use it to pull the new wire), then replace that QO load center with a subpanel that I can run both 110 and 220V branches from?

Or do I even need the ground wire from the house if there is a grounding rod in the garage?

If you're going to pull a cable, make sure it's UF or some other cable suitable for underground. NM-b cable (AKA Romex) is not allowed underground or in wet locations.

 

[theoldwizard1]

actually one can do so, especially on a grandfather pre-2008 system like what the OP has. The issue is the equipment grounding conductor and neutral bonding.

From post #3 in the electrical FAQ:

3-wire feeders to detached structures that had no other parallel metallic pathways(eg. conduit, water and gas piping, communication cabling, etc.) were allowed up until the 2008 NEC code cycle.
3-wire feeder to detached building(no longer allowed as of 2008):

The issue becomes the INSPECTOR ! You have to understand the inspector is always right (except when they are wrong) ! From what I can see, the wire are all there, you just need to make certain they are connected to the existing equipment correctly and the neutral bonding was done according to the pre-2008 code.

 

[GreenEnvy22]

The issue becomes the INSPECTOR ! You have to understand the inspector is always right (except when they are wrong) ! From what I can see, the wire are all there, you just need to make certain they are connected to the existing equipment correctly and the neutral bonding was done according to the pre-2008 code.

OK so that looks like it would work, except that my conduit is metal. It says I can't have a metallic path other than the neutral wire?

 

[alfredeneuman]

OK so that looks like it would work, except that my conduit is metal. It says I can't have a metallic path other than the neutral wire?

The metal conduit all the way IS the ground.

 

[GreenEnvy22]

The metal conduit all the way IS the ground.

What does that note in the image about 'no other metallic path..." mean then?

 

[teamextreme]

It means if there isn't a grounding conductor (or a metal conduit in this case) there can't be any metallic paths (like a water line, or coax cable, etc.) The bonding jumper needs to be installed at the sub panel in this case as sberry pointed out. However, if you truly have metal conduit the entire length, then this whole discussion is moot, since you in effect have a 4-wire system. The bonding jumper shouldn't be installed in this case and you can just hook up the red wire and presto, 240v.

 

[GreenEnvy22]

It means if there isn't a grounding conductor (or a metal conduit in this case) there can't be any metallic paths (like a water line, or coax cable, etc.) The bonding jumper needs to be installed at the sub panel in this case as sberry pointed out. However, if you truly have metal conduit the entire length, then this whole discussion is moot, since you in effect have a 4-wire system. The bonding jumper shouldn't be installed in this case and you can just hook up the red wire and presto, 240v.

The conduit only runs the external portion, so where the armored wire leaves the house, until it enters the garage.

However since I want gfci, after looking at the cost of 220 volt GFCI Breakers, I think I'll just stick with multiple 110-volt circuits.

I will check for continuity and impedance to either end of that conduit, just to make sure it is an unbroken connection, at least that part of it.

I'm unsure why they never hooked up the red wire to get the second leg. Right now all the breakers in the garage or running off of that one leg, which causes it to trip. I think I'll hook up the red and move over one of the breakers

 

[Zeke]

There are 2 ways to "hook up" the red wire and one is wrong, the other way is what has been discussed so far. Don't do the wrong thing (on the same phase, or providing a multiwire branch circuit). To my knowledge, a MWBC circuit is not allowed to power an out building. 2 circuits on the same phase sharing a neutral is clearly wrong.

I just brought this up so the folks in the know can discuss.

 

[TRWham]

There are 2 ways to "hook up" the red wire and one is wrong, the other way is what has been discussed so far. Don't do the wrong thing (on the same phase, or providing a multiwire branch circuit). To my knowledge, a MWBC circuit is not allowed to power an out building. 2 circuits on the same phase sharing a neutral is clearly wrong.

I just brought this up so the folks in the know can discuss.

An MWBC is specifically allowed to serve an outbuilding.

 

[sberry]

What Zeke means is put it on a 2 pole breaker. I was in a panel that was crowded a while back. The last guy that worked in it was a genius and a master. He wasn't a guy to do a lot of extra work. Had multi wires hooked up everywhere and a sump with a different breaker, confused the **** out of the handyman.

 

[TRWham]

There is no way to provide a permissible MWBC with 2 lines from the same phase. Doing so is just a shared neutral and not permitted. By definition, an MWBC consists of 2 or more ungrounded conductors with a voltage between them and a grounded conductor with equal voltage between it and each of the ungrounded conductors. An MWBC fed by non-adjacent poles is not permitted because it would not be possible to provide a common disconnect either by handle tie or multi-pole breaker to satisfy 210.4(B).

 

[alfredeneuman]

To my knowledge, a MWBC circuit is not allowed to power an out building.

If the outbuilding has a subpanel the feeder is a MWBC

 

[Zeke]

If the outbuilding has a subpanel the feeder is a MWBC

And still have only 120v? I don't think so. My point was that the 240v wiring options had already been discussed and solutions offered. I'll read the code regarding more than one feed to an outbuilding. To me that means one single breaker.

If he does do a double pole breaker at the main, all he has to do then is install a double pole breaker at the sub panel and then he has 240v. Are you suggestion that is OK?

 

[Norcal]

There are 2 ways to "hook up" the red wire and one is wrong, the other way is what has been discussed so far. Don't do the wrong thing (on the same phase, or providing a multiwire branch circuit). To my knowledge, a MWBC circuit is not allowed to power an out building. 2 circuits on the same phase sharing a neutral is clearly wrong.

I just brought this up so the folks in the know can discuss.

Only one circuit is permitted to run to a outbuilding, a multiwire feed is one circuit.

 

[alfredeneuman]

And still have only 120v?
If he does do a double pole breaker at the main, all he has to do then is install a double pole breaker at the sub panel and then he has 240v. Are you suggestion that is OK?

Yes as long he has 3 properly sized wires and the conduit is grounded

 

[theoldwizard1]

I'm unsure why they never hooked up the red wire to get the second leg. Right now all the breakers in the garage or running off of that one leg ...

That was the same way my son's garage was wired. Luckily the left enough of a tail in the main panel in the house that I was able to splice 12" of wire on to it an install a 240V 30A breaker. The garage had some weird cartridge fuse box (AC disconnect ?). It now has a proper panel more power than he will ever use (not likely to be welding)

However since I want gfci, after looking at the cost of 220 volt GFCI Breakers, I think I'll just stick with multiple 110-volt circuits.

Not cheap, but if you really want 240V GFCI install a spa GFCI/disconnect between the feed from the main panel and the sub-panel.


Segue - I sure there is "logic" behind the change in code for feed to detached building that happened in the 2008 NEC, but how "necessary" was it ? In the previous 60 years how much property damage occurred and how many live were lost using the "3 wire system" ?

The same question applies to both tamper resistant outlets and AFCI. They look more like a way for electrical equipment manufactures to increase the profit margin !

 

[theoldwizard1]

To my knowledge, a MWBC circuit is not allowed to power an out building. 2 circuits on the same phase sharing a neutral is clearly wrong.

Admittedly not a professional, but I am pretty sure MWBC must be on separate legs. This is why they can share the same neutral. Clearly this means no tandem breakers.

 

[rlitman]

Admittedly not a professional, but I am pretty sure MWBC must be on separate legs. This is why they can share the same neutral. Clearly this means no tandem breakers.

They do make tandem breakers that serve two poles. But a typical tandem does not.

And while a true MWBC certainly can feed an outbuilding, supplying both hots from the same leg is not a MWBC, and is dangerous.

 

[TractorJeff]

This Thread looks "de-railed"!
I am pretty sure the OP meant he was going to attach the Red wire to the other Fuse slot which on those old Edison boxes would put him on the other 120 volt leg! Following 2008 Code, he then would have 240 in his garage. Pull the Fuse Block disconnects the circuit!
As far as the 240v GFCI, I ask why he thinks he needs it?

 

[Norcal]

They do make tandem breakers that serve two poles. But a typical tandem does not.

And while a true MWBC certainly can feed an outbuilding, supplying both hots from the same leg is not a MWBC, and is dangerous.

Only twin breakers that can supply 240V is GE which only work in GE panels, and now obsolete/out of production, Challenger, & Crouse-Hinds, otherwise a quad breaker of the appropriate make is required,

 

[Zeke]

I just wanted to clear my part of this up. We all know, and hopefully the OP knows, that bringing current to the red wire cannot be from the same buss as the black. Said and done. What's left is the possibility of a MWBC. I did not know that was possible to an outbuilding. Then other possibility is a 240v supply to the existing panel in the garage. This is depending on the existing wire size. No point in doing 240v on 12 ga. or less as providing branch circuits in the garage would be limited to that which can be done with, say a 20 A MWBC on 12 ga. IOW, no ability to have both 120v individual circuits AND a 240v circuit in that existing panel unless the wire ga will support that.

Seems like the discussion did go 'off the rails' a bit but it's been an informative thread.

Now we must get down to brass tacks and determine what exactly this "armored cable" has AFA wire gauge.
And since the OP is not likely to change out the fused circuit to the garage, talk about tandem and quad breakers is moot.

One more thing: looking at Post #1 and the pics, I don't see how 3 breakers in a row on one side of that subpanel are all on the one leg. What am I missing there?

 

[TRWham]

An MWBC is only allowed to serve line to neutral loads (210.4(C)).

 

[TRWham]

I...

One more thing: looking at Post #1 and the pics, I don't see how 3 breakers in a row on one side of that subpanel are all on the one leg. What am I missing there?

Look closely and I think you will see that panel is split so one bus feeds one group of breakers on one side from one line, and the other bus is on the other line.

 

[Zeke]

Look closely and I think you will see that panel is split so one bus feeds one group of breakers on one side from one line, and the other bus is on the other line.

I couldn't tell if that buss stopped at the breaker on the right or went under it. Weird set up but you have to be correct if the 3 circuits were functioning.

So the only way the OP could possibly use a 240 breaker is to position it in the center bridging both busses. Or do they even make that breaker?

 

[rlitman]

An MWBC is only allowed to serve line to neutral loads (210.4(C)).

Incorrect. Exception #2 allows for 240V loads on a MWBC when a breaker that trips both poles together is used.

Handle ties cover 210.4B for line to neutral loads, but for 240V line to line loads, you need a manufactured two pole breaker. Fuses of course are not acceptable.

 

[NUTTSGT]

Seeing how the OP lists "Niagara Region" as his location and the first attached picture shows the cartridge fuses mounted sideways, I'd guess the OP is possibly in Canada.


If he is, I don't know how much the NEC corresponds with the CEC. Just wanted to throw that out there.