retrofail

Electrical advice needed for my detached shop/man cave/smoke lounge

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I have a detached garage that already has power ran (underground) from the main electrical panel in my attached garage. Power ran includes lighting, 110 outlets and at least one 220 outlet. But there isn’t a separate sub panel in the detached garage. 

My first question: isn’t it unusual to have all that power ran without a sub panel in the detached garage?  

And second: how hard/expensive would it be to install a subpanel? Or do I even need to?

I ask because I’d like to fully insulate it and install a 240v heater as well as run all the fun 240v shop tools. 

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It’s not necessarily unusual. It’s possible whoever installed the wiring ran separate circuits to the lighting and outlets.

installing a sub panel should be fairly easy, especially if the existing wiring is run in conduit. If it is, you can trace the conduit to where it comes out of the ground, and redirect it to the location you want to install the sub panel. Then, you would pull out the existing wires and install new, sized for current draw you anticipate needing for everything you want to feed out of the sub panel. Last, you would run the wiring for your existing lighting / outlets into the new panel, and run new wiring for the heater.

if you have direct burial cable run to the garage, it becomes a bit more difficult as you would need to dig a new trench for the new wiring.

Either way, it’s not a big deal, and depending on circumstances (location of main electrical service relative to the garage, and whether or not you already have a conduit from the main house to the garage) may not be too expensive.

I hope this helps. If you have any more questions, please feel free to reach out and ask.

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Warren   

Yes ideally you should have  a sub board with breakers for power and light. if the cable you have for the power circuit you now have has a high enough amp rating you could turn it into the sub main and install a sub board in the garage.

Do you know where the power to the garage is fed from. Do you have just one breaker that feeds it or is there a separate breaker for power and light.

If there is just one breaker have a look at what the amp rating is on it.

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1 hour ago, Projectal said:

I hope this helps. If you have any more questions, please feel free to reach out and ask.

Awesome, man! Thanks.  The wealth of information on this board is phenomenal. 

1 hour ago, Warren said:

Yes ideally you should have  a sub board with breakers for power and light. if the cable you have for the power circuit you now have has a high enough amp rating you could turn it into the sub main and install a sub board in the garage.

Do you know where the power to the garage is fed from. Do you have just one breaker that feeds it or is there a separate breaker for power and light.

If there is just one breaker have a look at what the amp rating is on it.

The power is on separate breakers on my main panel. Separate breakers for lights and outlets. And a two pole breaker for the 240v. Not sure if separate breakers helps or hinders my situation. I’m assuming more amps is better in this case. 

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Warren   
49 minutes ago, retrofail said:

Awesome, man! Thanks.  The wealth of information on this board is phenomenal. 

The power is on separate breakers on my main panel. Separate breakers for lights and outlets. And a two pole breaker for the 240v. Not sure if separate breakers helps or hinders my situation. I’m assuming more amps is better in this case. 

It's not so much the voltage you need to take into account but the amps. If you are using one of the feeds to the garage as a sub main it needs to be big enough to handle the combined amps requirements of everything you plan to run in the garage, lights plus power points. At the sub board you then split that cable up to feed a breaker for your lights and a breaker for your power points. Of course here in Australia we only have 240v for all our domestic requirements. I'm not sure how they feed the different voltages to the load in the USA.

If in doubt always best and safest to consult your local electrician.

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21 minutes ago, Warren said:
1 hour ago, retrofail said:

 

It's not so much the voltage you need to take into account but the amps. If you are using one of the feeds to the garage as a sub main it needs to be big enough to handle the combined amps requirements of everything you plan to run in the garage, lights plus power points. At the sub board you then split that cable up to feed a breaker for your lights and a breaker for your power points

Exactly right^^

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PigFish   

Are you running a welder, a compressor, HVAC and other high load equipment in your 'man cave?' Do you need many circuits, where multiple home runs back to the main panel would make the project expensive and lossy? Do you have limited room for additional circuits in your main panel?

Typically, you will find regional electrical rooms and sub-panels in situations where long runs and multiple runs will lead to losses and high expenditures. It makes more sense to bring large feeders into an electrical room, and break out circuitry locally in a vicinity close to the appliances that will be using the power.

If you have existing wiring to meet your needs, why even consider a sub-panel? I would only consider it if I were thinking of bringing in one set of feeders, perhaps large enough to accommodate for long runs, where the power requirements would necessitate such work.

If the circuits are already wired, why rewire for zero gain?

I have a sub-panel that supplies my shop. It allows for me to bring one set of feeders to the panel, reducing the home runs for circuits back to the main panel. Furthermore it allows for local disconnects for my power. It also allows for flexibility in the makeup of the sub-panel, future improvement and additional circuits. It was a necessary expense in my case.

I have two welders, one compressor, several 240V tools including my CNC on my sub-panel. It provides a close disconnect for many of those tools... and short runs back to the panel for those tools. If you are going to need several 240V dedicated circuits, with disconnects, using your existing conduit to rewire a sub-panel might be the best move. Furthermore a sub-panel will allow you the flexibility of 'spares.' A good idea for a growing shop.

Cheers! -R

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Thanks @PigFish  

At present, the current layout works as the only 240v item out there is my compressor. But that’s temporary. Eventually, I’ll have the compressor, welder, and likely a heater. And room for additional circuits would be nice. 

At this stage I’m still in the research and planning phase. Determining what I want to do, what I can do myself and what I should hire out. 

It looks like installing a subpanel will be a necessity. I’m Nervous Nelly around electrical work. So, I’ll definitely hire professional help. But being able to convey exactly what I want to them and knowing I’m not getting ripped off is important to me. 

Thanks for all the input gents

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First you would need to know what capacity your mainbreaker in the house is and if it could handle a subpanel in the garage.You might have to upgrade your incoming power first 

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20 minutes ago, Squarehead said:

First you would need to know what capacity your mainbreaker in the house is and if it could handle a subpanel in the garage.You might have to upgrade your incoming power first 

200 amp

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31 minutes ago, retrofail said:

200 amp

In that case you should be ok but also keep in mind what your requirements are for your house.Do you have electric heat in your house which is the biggest hydro consumer.in any case you should be able to run a 60-80 Amp subpanel to your garage.Check the existing wiring if suitable to carry the load or replace with larger gauge wiring.Not to forget that you need a 2 pole breaker in your mainpanel to supply you subpanel in the garage.You need that anyways as you want to get 240vac equipment in it.

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Just for clarification, here’s my current setup:

200 amp panel

BBDD1C42-7934-4C8C-83AB-62EF7C3A8989.thumb.jpeg.258d4b84dad2f72cfa3d384c40289928.jpeg

2 of these 20 amp breakers supply the lights and 110 outlets

2613952E-802B-4C18-B948-C74DFA5211A0.thumb.jpeg.ab1245135e25fc1df608be4bd71296d6.jpeg

And the bottom two-pole breaker supplies the 240V

D6F639AD-4E34-42AC-B8D8-D38246126805.thumb.jpeg.4157122dc2ba4e33c3b8dc76c28c3271.jpeg

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Just for clarification, here’s my current setup:
200 amp panel
BBDD1C42-7934-4C8C-83AB-62EF7C3A8989.thumb.jpeg.258d4b84dad2f72cfa3d384c40289928.jpeg
2 of these 20 amp breakers supply the lights and 110 outlets
2613952E-802B-4C18-B948-C74DFA5211A0.thumb.jpeg.ab1245135e25fc1df608be4bd71296d6.jpeg
And the bottom two-pole breaker supplies the 240V
D6F639AD-4E34-42AC-B8D8-D38246126805.thumb.jpeg.4157122dc2ba4e33c3b8dc76c28c3271.jpeg

Hi retro hail I am an electrician. I would recommend you getting qualified electrician for your answers obviously, but looks like you need at least a 60 amp feed number 6/3 awg for your garage. Do not use existing feed wire as it's only 30 amps and won't handle your compressor and heater at the same time. Your electrician will do a load calculation to see amperage you will need.




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9 minutes ago, smokealot said:


Hi retro hail I am an electrician. I would recommend you getting qualified electrician for your answers obviously, but looks like you need at least a 60 amp feed number 6/3 awg for your garage. Do not use existing feed wire as it's only 30 amps and won't handle your compressor and heater at the same time. Your electrician will do a load calculation to see amperage you will need.




Sent from my iPad using Tapatalk

Thanks. I’ll definitely have an electrician do the work. Getting an idea of what I’m in for and this helps a ton. I knew the members here would be very helpful. 

Cheers!

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Easiest would be to just fish another 30 amps (10 gauge) through your existing conduit (if it's roomy) and put another double breaker in the blank space in your existing box.  Like that you get the extra outlet to run one of your big items (heater, welder, etc.)  It's convenient to have a sub panel in your detached garage, but not necessary.

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Also consider voltage drop for the length of the run. If close to 200' you may want up size the wire run.

Sent from my SM-G900V using Tapatalk

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34 minutes ago, Stogiepuffer said:

Also consider voltage drop for the length of the run. If close to 200' you may want up size the wire run.

Sent from my SM-G900V using Tapatalk
 

From the main panel to where it enters the shop is less than 50’, so I’m not too concerned about that aspect. 

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