Sub panel electrical questions

craveman85

CJ-8 Member
CJ-8.com Member
City
Dolgeville
State
ny
#1
I'm moving this month and need to install a sub panel in the small garage located at the new place. I'm planning on a 100 amp panel that's located about 120' from the 200 amp main box. The stove, water heater, boiler, and dryer all run on natural gas so I have plenty of juice. I have more than enough 2" schedule 40 conduit for the whole run including the inside stuff. I'm kinda having a hard time deciding which wire to run. I've been cramming on nec stuff lately and I'm still kinda confused. I'm thinking 3 individual #1 copper thhn wire and one #3 for a ground. This sound right to you guys? I'm sure there's a couple people on here that are knowledgeable in electrical work and nec codes. I'm looking to do it myself because I may go into the electrical field soon. Need a change in career and it seems like a good way to go.
 

craveman85

CJ-8 Member
CJ-8.com Member
City
Dolgeville
State
ny
#3
Can you use 4 of the same color of thhn as one cable if I mark the ends with colored tape? I can get #1 copper locally but only in black locally for aluminum all I can get is #2 which I believe has to be derated at 75 amps for a 60° rating. Or 4/0 which is too damn big to work with for my needs.
 

BRKLYNZ28

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
BROOKLYN
State
NY
#4
I'm moving this month and need to install a sub panel in the small garage located at the new place. I'm planning on a 100 amp panel that's located about 120' from the 200 amp main box. The stove, water heater, boiler, and dryer all run on natural gas so I have plenty of juice. I have more than enough 2" schedule 40 conduit for the whole run including the inside stuff. I'm kinda having a hard time deciding which wire to run. I've been cramming on nec stuff lately and I'm still kinda confused. I'm thinking 3 individual #1 copper thhn wire and one #3 for a ground. This sound right to you guys? I'm sure there's a couple people on here that are knowledgeable in electrical work and nec codes. I'm looking to do it myself because I may go into the electrical field soon. Need a change in career and it seems like a good way to go.
Depending on the state you live in and if this is going to be inspected. There are. Many answers so ill give you nyc law you will have to run 4 #1awg copper. Problem is its very hard to find #1 so your most likely have to buy 1/0 . Its the 120 feet is the problem. voltage drop will happen and that reason for upsize of the wire size. Normally i would run 4 thhn #2 wire and call it a day. 2 wire is rated for 105 amps at 100 feet. I would measure again to see if it really is 120 feet. Keep in mind a roll of wire is 500 feet and ground wire green in ny has to be the same diameter of the mains. So 1 roll will make it. You might be able to get away with downsized. Again that up to your code state. You could also stick a 80amp breaker on that wire and be good.. do you really need 100 amps? Did u do a load calculation? Most houses in ny with garages only are allowed 100 amp mains. Unless you have a variance for some reason. Also if your using pvc your going to have to put in a bonding wire of #6 bare. And if you want to use aluminum you going to have to upsize it again as aluminum isnt a good current carrier . The chart shows your wire size fill . The price from #2 to 1/o is alot. . So measure again. And this is nyc code ..we special :)...
 
Last edited:

BRKLYNZ28

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
BROOKLYN
State
NY
#5
For the other question nyc wants every wire its own color. No banding. This is new to us so most likely you can just use color tape at the ends to the pipe. I been doing it for years. They feel if the tape dries out it migjt fall off and the next person wont be able to identify.
 

craveman85

CJ-8 Member
CJ-8.com Member
City
Dolgeville
State
ny
#6
We're allowed bigger mains out here. I don't think any code for anything from nyc applies up here at all lol. Most newer buildings up here have a minimum of 150 amp and detached garages. I'm going to have it inspected. My compressor runs at 26 Fla. Startup is higher. Running a 20v leg to the chicken coop, got a plasma cutter that will run the same time as the compressor, lights, 2 20 amp outlet legs, a refrigerator for aging meats, another for soda, possibly a pool eventually. I could probably get by with 80 but eventually plan on upsizing the garage to a 24x60'building.
 

craveman85

CJ-8 Member
CJ-8.com Member
City
Dolgeville
State
ny
#7
I tried contacting the local code enforcer/inspector guy but he's on vacation for a couple weeks. I was reading that I need to use the lowest temperature rating in the whole circuit to see which column I have to use on the ampacity charts, the main box, my 100 amp breaker in the main, my sub panel, and my main in the sub are all rated at 75°c. The wire I'll probably use is rated at 90. This means I could go with 3awg copper. It's 100 amp@75° I can buy that by the 500' roll locally. I'm hoping local code will allow the same color wire. Hell they let us have up to 10 chickens in village limits. We don't even have water meters here.
 

craveman85

CJ-8 Member
CJ-8.com Member
City
Dolgeville
State
ny
#8
I ran rope where I'm going to run the wire. I got 115 feet where I'd have all the conduit run. I could save a few feet if I were to drill a hole through the 2' foundation wall but a hole saw through a normal wall is much easier.
 

BRKLYNZ28

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
BROOKLYN
State
NY
#9
I tried contacting the local code enforcer/inspector guy but he's on vacation for a couple weeks. I was reading that I need to use the lowest temperature rating in the whole circuit to see which column I have to use on the ampacity charts, the main box, my 100 amp breaker in the main, my sub panel, and my main in the sub are all rated at 75°c. The wire I'll probably use is rated at 90. This means I could go with 3awg copper. It's 100 amp@75° I can buy that by the 500' roll locally. I'm hoping local code will allow the same color wire. Hell they let us have up to 10 chickens in village limits. We don't even have water meters here.
Ok so your acually good without upsizing. Your voltage drop is only 1.2percent nyc code no more then 3percent . I would do #2s if u can get #1s for a few bucks more even better
 

BRKLYNZ28

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
BROOKLYN
State
NY
#10
I want a chicken lol. I wish i had no water meter would save me 100 bucks a month
 

FLCJ8

Legacy Registered User
City
Palm Bay
State
FL
#12
I'm moving this month and need to install a sub panel in the small garage located at the new place. I'm planning on a 100 amp panel that's located about 120' from the 200 amp main box. The stove, water heater, boiler, and dryer all run on natural gas so I have plenty of juice. I have more than enough 2" schedule 40 conduit for the whole run including the inside stuff. I'm kinda having a hard time deciding which wire to run. I've been cramming on nec stuff lately and I'm still kinda confused. I'm thinking 3 individual #1 copper thhn wire and one #3 for a ground. This sound right to you guys? I'm sure there's a couple people on here that are knowledgeable in electrical work and nec codes. I'm looking to do it myself because I may go into the electrical field soon. Need a change in career and it seems like a good way to go.
John,
First off, good for you on attempting this project and studying to learn the trade. The need for quality electricians is not going away, the people willing to work in a labor intensive trade is.
Now to your questions:
All electrical installations in the US are based on the National Electrical Code (NEC). The NEC is not the "gold standard", it is the minimum requirements.
Each jurisdiction decides when they will enforce the latest edition of the code, and what additional requirements above the Code minimums they choose to enforce.
Also, you will find the inspectors in your area can have different interpretations of what the NEC requires. Unfortunately the inspector (Authority Having Jurisdiction - AHJ per the NEC you have been reviewing) typically has the final say. As BRKLNZ28 mentioned his AHJ has set requirements above the NEC minimums.
I've probably already said too much without actually answering your questions, but the short answer is there are several questions about your installation that need to be addressed before an informed design layout can be made.
I'll PM you with some questions and info to help you accomplish a safe and reliable installation that will pass inspection in your area.
 

craveman85

CJ-8 Member
CJ-8.com Member
City
Dolgeville
State
ny
#13
Purchased a 500' roll of #2 from home depot. Normally like 430$ a friend who's a manager there got me 10% off and I had a 10% credit card deal. Then next week I'll pay off the card and forget it exists.
 
Top