100 Amp Service

[s1nemesis1s]

Hello all,

I am looking to run 1.5 conduit underground 100 feet to my garage. I want 100 amps of electrical service - 2-2-2-4 wire URD or should I look at copper? WOuld copper 4-4-4-6 support it?

I am not worried about code because I am away from all that - but I don't want to burn my house down.

 

[Megawatt]

Hello all,

I am looking to run 1.5 conduit underground 100 feet to my garage. I want 100 amps of electrical service - 2-2-2-4 wire URD or should I look at copper? WOuld copper 4-4-4-6 support it?

I am not worried about code because I am away from all that - but I don't want to burn my house down.

100 amp requires # 3 wire copper and since you already have a conduit installed if I was you I would pull three # 3 THHN copper wires and one # 6 ground copper. It’s a little more expensive but a whole lot easier to work than aluminum but. Good luck

 

[Megawatt]

100 amp requires # 3 wire copper and since you already have a conduit installed if I was you I would pull three # 3 THHN copper wires and one # 6 ground copper. It’s a little more expensive but a whole lot easier to work than aluminum but. Good luck

Since you don’t care about the code # 4 copper would work because you will probably never pull 100 amps

 

[s1nemesis1s]

Since you don’t care about the code # 4 copper would work because you will probably never pull 100 amps

What is the max it allows - I am confused.

 

[s1nemesis1s]

So let me ask would 2-2-2-4 URD work?

 

[Megawatt]

What is the max it allows - I am confused.

# 3- 110 amps copper # 4 90 amps copper

 

[Megawatt]

# 3- 110 amps copper # 4 90 amps copper

My advice is to do it right with at least 125 amp main lug only panel installed in your garage. That’s a lot of amperage and your own house doesn’t probably worst case pull 50 amps at one time. I’ve wired MANY garages and buildings and usually just pull # 8 copper and never had a complaint. Your not going to burn your house down. I think that since you are a DIY you need to at least consult an electrician. There’s many things in the NEC that your not aware of and safety is the upmost importance.

 

[s1nemesis1s]

I keep seeing this come up Al MHF wire:

https://www.menards.com/main/electrical/electrical-wire-cable/electrical-service-wire-cable/2-2-2-4-aluminum-mobile-home-feeder-per-foot/3692059/p-1473854610601.htm

I like the price - I want a main disconnect in the garage as well - Can I run this in conduit? Anything wrong with the wire other than its aluminum? Any box recommendations? I need maybe 6-10 circuits, thinking a 90mp breaker.
Or should I go copper - and if so, what gaige 4-4-4-6? The alumnium is just so much more affordable.

 

[Megawatt]

I keep seeing this come up Al MHF wire:

https://www.menards.com/main/electrical/electrical-wire-cable/electrical-service-wire-cable/2-2-2-4-aluminum-mobile-home-feeder-per-foot/3692059/p-1473854610601.htm

I like the price - I want a main disconnect in the garage as well - Can I run this in conduit? Anything wrong with the wire other than its aluminum? Any box recommendations? I need maybe 6-10 circuits, thinking a 90mp breaker.
Or should I go copper - and if so, what gaige 4-4-4-6? The alumnium is just so much more affordable.

My friend just go with the aluminum it’s just a personal preference so instead of a main lug only panel buy one that already has a main breaker in it. They have 12 circuits and 26 circuits at Home Depot and Lowe’s. The breaker that’s already in it will be probably a 125 amp breaker, just replace it with a 90 amp double pole breaker. Yes you can pull either Aluminum or copper in a 11/2 conduit

 

[s1nemesis1s]

Thank you - this makes it so much easier and helps demystify the process. What size/sort of breaker should I put in at my main box? Should it be a 90 to match?

 

[Megawatt]

Thank you - this makes it so much easier and helps demystify the process. What size/sort of breaker should I put in at my main box? Should it be a 90 to match?

Yes that way you will have a discount in your new panel

 

[norcal]

It sounds like the garage is detached so unless having 6 or fewer circuits, a main will be required + a grounding electrode, such as a Ufer, AKA a concrete encased electrode, or a couple of ground rods driven at least 6 feet apart.

 

[Megawatt]

It sounds like the garage is detached so unless having 6 or fewer circuits, a main will be required + a grounding electrode, such as a Ufer, AKA a concrete encased electrode, or a couple of ground rods driven at least 6 feet apart.

NorCal you are not required to have ground rods on a sub fed panel. All the bonding takes place at the main service panel. You have to pull 4 wires to the building and add a ground bar if it doesn’t have one and isolate the grounds from the neutrals.

 

[norcal]

NorCal you are not required to have ground rods on a sub fed panel. All the bonding takes place at the main service panel. You have to pull 4 wires to the building and add a ground bar if it doesn’t have one and isolate the grounds from the neutrals.

If in the same structure then not required, but in a separate structure yes they are required, just no bond between the neutral & grounding conductor in the subpanel, & the grounding electrode conductor would land on the ground bar.

 

[Megawatt]

If in the same structure then not required, but in a separate structure yes they are required, just no bond between the neutral & grounding conductor in the subpanel, & the grounding electrode conductor would land on the ground bar.

You will need to find the article in the NEC which you should know is article 250 of the NEC