Sub panel questions and help needed

[Leeboy20]

Hi everyone ...I'm helping my neighbour finish off his bathroom on the side of his old garage. It has a heated floor mat installed and one of those mulching toilets and a couple of receptacles and a fluorescent light .
Here's where it gets tricky for me. His house panel is totally upgraded a few years back to 200 amps. But the single wire running out to the garage were not sure the amps. I'm hoping my friend brings his clamp on multimeter tomorrow. So, as of now, all the single wire is powering is 3 , 8 foot tube lights, a garage door opener and a couple of plugs inside and out. The new bathroom heated flooring requires its own circuit it says . My idea was to add a 60 amp sub panel and leave the original garage circuits on one breaker, add a 2nd for the heated flooring and a 3rd for the toilet and maybe a new plug or two. My question is what do I need to do or check to make this all work ? Or is this impossible and better off digging a new wire to the garage? ( which means lifting paver bricks up etc etc ....)

 

[bmxdad]

Single wire? What does the breaker to the garage say? Is the garage detached or part of the house? If detached, as far as I know, you can have only one circuit to it.

If it's attached, it's all open.

 

[Leeboy20]

It's detached , they kinda went and did all this ( in floor heating , electric toilet ) before they even checked the breaker ( which isn't even marked on the main panel ) that's tomorrow's job . It's all ready at the point of no return, so basically gotta make it happen the proper way .

 

[acer66]

As bmxdad said only one feed to a detached garage here in the US but it might be different in Canada.

But honestly I do not see a reason to leave the old feed anyway since it sounds like there is already a bunch of stuff on there which could use some sorting out.

I for instance would not have lights and plugs on the same circuit.

But that of course depends also how the garage is used.

Well, long story short I would run some wire for a sub panel and run the old circuit(s) from there.

 

[Leeboy20]

If we run a new wire for a sub panel . What gauge would we want ? There will never be a 240v receptacle in the garage , just lights, plugs, the heat mat and electric toilet .

 

[wyliesdiesels]

Sounds like u have a light load. What is the distance from panel to garage?

And yes in THE US, u cant have more than one feed to a detached structure.

 

[bentleyden]

you can use 6 gauge if your run is less than 75feet on 60amp.

 

[CNGsaves]

Future homeowners will appreciate it Being Done Right !! Also, they may have MORE electrical needs so the 60A subpanel (or even 90A) in detached garage would be ideal for most any one person shop.

I'd vote for retrenching 2" plastic conduit to proper depth (local code) and use the tried-and-true (and cheap) MHF aluminum 2-2-2-4 that's around $1.50/ft. Backfill 12" dirt in trench then put in 1" plastic conduit for low voltage stuff like internet, CATV, security, phone, etc. If short enough run, the above affordable MHF wire will give you 90A in the detached garage. Don't forget 2 ground rods on the detached garage as well.

 

[pattenp]

you can use 6 gauge if your run is less than 75feet on 60amp.

How did you come up with 75ft on 60A?

 

[Slowgsr]

Future homeowners will appreciate it Being Done Right !! Also, they may have MORE electrical needs so the 60A subpanel (or even 90A) in detached garage would be ideal for most any one person shop.

I'd vote for retrenching 2" plastic conduit to proper depth (local code) and use the tried-and-true (and cheap) MHF aluminum 2-2-2-4 that's around $1.50/ft. Backfill 12" dirt in trench then put in 1" plastic conduit for low voltage stuff like internet, CATV, security, phone, etc. If short enough run, the above affordable MHF wire will give you 90A in the detached garage. Don't forget 2 ground rods on the detached garage as well.

No ground rods - in Canada our services are only grounded at the point of entry to prevent ground loops (I don't buy it but I follow the rules)

Pull the bonding screw in the subpanel and be sure to run a ground from your house panel

Burry some 3/3 cu teck90 and fuse it @ 90a. It's fast and efficient and ground movement/frost freeze won't cause it to fail. Unless your going below frost the conduit will break in the ground and fail long term.

 

[Leeboy20]

Thanks everyone, renting the ditch witch on Friday

 

[tfi racing]

3/3 Teck? Must be nice to be rich and piss away cash like that!ACWU will get the job done for a fraction of what copper costs...

 

[Leeboy20]

I have aluminum to my sub panel as well to my hot tub breaker. But back to my neighbour . Looks like we have a problem. He has a 200 amp main service . Then a 100 amp sub panel which is pretty much full. ( see pic) there is one free breaker and the other 15 amp runs only his small deep freeze which he could eliminate and potentially freeing up 30 amps. At this point he would be happy with just the heated floor mat working safely. It's 10 amps . Any advice now ?

 

[buddyboy]

looks like you have room there for 5 (maybe 9) more breakers

maybe I'm looking at it wrong, i'm not an electrician

 

[wyliesdiesels]

I have aluminum to my sub panel as well to my hot tub breaker. But back to my neighbour . Looks like we have a problem. He has a 200 amp main service . Then a 100 amp sub panel which is pretty much full. ( see pic) there is one free breaker and the other 15 amp runs only his small deep freeze which he could eliminate and potentially freeing up 30 amps. At this point he would be happy with just the heated floor mat working safely. It's 10 amps . Any advice now ?

Youre calculating things wrong.

U dont add up all the breakers to figure out what headroom u have left with the feeder ampacity.

U need to do load calcs to figure out how much load u can add.

The hot tub will likely very seldomly use 50a much less 40a.

Not sure what kind of load is in the pump room but i doubt its 30a...

 

[Leeboy20]

We can't find a amp rating on the electric toilet , the heat mat uses 10 ... And 1 light and a couple of plugs is what he wants to do. He has no interest in 240V he says .

 

[Leeboy20]

Here is the sticker on the pump house

 

[Sokoloff]

You're going to want to put a subpanel in the outbuilding and a single feed to that. Then, run as many circuits in the garage as needed. You are only allowed a single feed to an outbuilding in the US, and that's a sensible requirement.

Whether they want 240VAC or not in the garage is largely irrelevant. Providing it is the cheapest and most effective way to give them what they do want, which is the ability to run several different electrical loads in the garage without mickey mousing things.

Give them at least a 60A, 240VAC feed and they're safe, sound, and set for what they need and any reasonable future need (electric car, compressor, welder) at a reasonable cost.

 

[wyliesdiesels]

The OP is in Canada so codes may be different than the US.