240 and 120v from 240 source

[theonetrueruss]

I have a background in elect eng though I really do computer stuff so my electrical knowledge is a bit rusty.

I have a 240V circuit that I am powering my HLT with currently.. working great. Going through a spa panel for GFCI etc.

I am planning to upgrade my setup to use an in panel GFCI breaker so I can get rid of the spa panel (it is in the way and wired up ugly etc) and have a nice clean outlet in the wall that I plug into.

no problems or questions there

Right now I am running a 3 conductor cable from my spa panel to my brew rig (+ and - 120V and ground)

I would like to be able to leave the same long run of 3 conductor cable in place but would also like to run a 120v outlet off of it.

I am only pushing 4500watts on my element so the power consumption should not be a problem - it is all 30 amp capable wiring.

Here is the question:

Assuming I fuse things properly, is there any problem with using the +120 and Gnd to power the 120 v outlet? Just going to power a light, a pump, and a temp controller with it. This will eliminate an extension cord I currently run to a 120V outlet to power these things.

(After this upgrade next is building a control panel - right now I have lots of wires and a couple electric boxes etc.. on a shelf. not pretty but safe and effective. Panel will be pretty.. but will be many months before I can spare the time for that build.)

 

[jeffmeh]

The short answer is do not do it. It will not be safe, and should trip your GFCI breaker if you try to run 120v off H-G. You need 4-wire (H-H-N-G), and run 240v with H-H-G, 120v with H-N-G.

 

[peachcarmelsoda]

on second thought dont do it.

I was wondering this the other day myself.

like what if you twisted the earth ground wire at the spa panel to the to the HLT. So you have proper ground to the HLT. Also connecting the ground wire from the "Brew Run" to the eath ground at the spa panel. So your grounds are taken care of.

And then connect the neutral wire from the "Brew Run" to the naked ground returning to the Breaker panel.

And twisting the "brew run" hot to one of the hot wires where the spa panel used to be.


___

I think the answer of dont do it lies in the longevity of the cable where the wire should be coated being a neutral carrying current and not an uncoated wire.

If i was on the moon and had to do it to get buy i would.

 

[BadNewsBrewery]

This question seems to pop up at least once a day. The codes have changed, and for good reason. Neutral is for carrying voltage on the return run. Ground is for carrying stray voltage in the event of a failure. Using your safety (ground) as a regular run is not the safest way to do things, and when you're playing with electricity, safe is the way to go.

Replace the 3 wire run that you have with a 4 conductor run and bring Hot A, Hot B, Neutral, and Ground to your panel. Then you can run all the 120v or 240v things you'd like (within the amperage rating of your wiring / breaker) in the method jeffmeh described above. H-H-G or H-N-G

 

[raouliii]

I'll throw in a few basic, de-rusting, comments to add to the mostly good advice already given.

There are no +'s and -'s in AC power distribution.

In a three wire, single-phase system, the two phase conductors are usually referred to has L(ine)1 & L(ine)2 or H(ot)1 & H(ot)2 and are colored black and red. There is 240vac between L1 to L2.
The grounded conductor is usually referred to as N(eutral) and is colored white. There is 120vac between Neutral and either L1 or L2.
The grounding conductor is usually referred to as G(round) and is colored green or bare copper.

In a 120vac circuit the exact same current is carried on the Line and Neutral conductors of the circuit.
In a 240vac circuit the exact same current is carried on Line1 and Line2 conductors of the circuit.
Current is not consumed by the load.
The neutral conductor should not be used as a ground and the ground conductor should not be used to carry load current.
Neutral is never connected to ground except in the primary service disconnect panel and is usually accomplished by jumpering the neutral buss bar to the ground buss bar. Downstream sub-panels should have separate buss bars.

FWIW, I also recommend using a 4-conductor cable for the 240/120 circuit you desire.

 

[theonetrueruss]

got it... thanks.. I'll just have to wait until I run 4 conductors to my rig to put in a 120 as well as the 240.