jtomara37

I live in New Hampshire USA.

I am working on supplying the feed for a RTU for a walk-in freezer.
The unit is 3 phase
The Max overcurrent protection for the unit is 30 Amps.
the length of the run is approximately 100ft
The job is at a restaurant

This is my plan:

1. The Panel is 120/240V 3 phase panel
2. The panel will have a 3-pole 30amp breaker
3. Will come out of the panel with 10-4 MC or Flex with THHN (black, red, blue, green) for about 25ft to a 6x6 metal j-box near the outside wall basement of the restaurant
4. From the 6x6" j-box will run a short stub 3/4" conduit to a 3/4" emt compression connector which will be screwed into the 3/4" LB on the outside wall of the restaurant.
5. From the 3/4" LB I will run along the outside wall of the restuarant with 3/4" EMT and compression connectors to a WP (weather proof) 3 phase Knife switch which will be mounted on the side of the RTU.

Questions:

1. What is the required size of the equipment (green) ground wire
2. Is the 6x6 j-box needed or could I get away with a 4x11/16" j-box
3. Is the 3 phase circuit required to be UNbroken to the unit or is it ok to splice within the junction box
4. Is the color code (black, red, blue, green) correct for this type of 3 phase application
5. Do electrical supply houses sell 10-4 MC with ground or would I have to use flex and fish the wires through it myself
6. When is it required to use a bonding bushing, would this application require it
7. Would a 3 phase knife switch be acceptable in this application or would I be required to put a 3 pole 30amp breaker disconnect on the unit instead of a knife switch

NOT going to do this>> but hypothetically if I were to run a white(neutral) wire would this require that I de-rate my 3 #10 tthn wires? Only 3 current carrying conductors are allowed in a conduit right? Is a neutral wire concidered a current carrying conductor?

Thanks in Advance for all the comments, suggestions and support.

Jerry

randomkiller

Surely you jest my good man, try the DIY site cause there's no way you belong on this one let alone running a three phase circuit. You did pull a permit for this work, right???

__________________
A Veteran - whether active duty, retired, guard or reserve - is someone who, at one point in his life, wrote a blank check made payable to "The United States of America," for an amount of "up to and including my life."

"One Nation Under God"

480sparky

Just because someone asks basic questions is not a reason for us to not respond. EVERYONE started knowing NOTHING about electricity. Where would this industry be if no one shared their experience?

Instead of simple answers, I'll give you some hints, though:

Table 250.122.

Quote:

Originally Posted by jtomara37 2. Is the 6x6 j-box needed or could I get away with a 4x11/16" j-box

314.16(B)(1).

Quote:

Originally Posted by jtomara37 3. Is the 3 phase circuit required to be UNbroken to the unit or is it ok to splice within the junction box

What do you plan on doing in the disconnect and back at the OCPD?

Quote:

Originally Posted by jtomara37 4. Is the color code (black, red, blue, green) correct for this type of 3 phase application

200.6 and 250.119.

Quote:

Originally Posted by jtomara37 5. Do electrical supply houses sell 10-4 MC with ground or would I have to use flex and fish the wires through it myself

25 feet?!?! Why not EMT all the way?

Quote:

Originally Posted by jtomara37 6. When is it required to use a bonding bushing, would this application require it

250.92(B)

Quote:

Originally Posted by jtomara37 7. Would a 3 phase knife switch be acceptable in this application or would I be required to put a 3 pole 30amp breaker disconnect on the unit instead of a knife switch

Why put an OCPD in a disco when you already have one back in the panel?

Quote:

Originally Posted by jtomara37 NOT going to do this>> but hypothetically if I were to run a white(neutral) wire would this require that I de-rate my 3 #10 tthn wires? Only 3 current carrying conductors are allowed in a conduit right? Is a neutral wire concidered a current carrying conductor?

310.15(B)(4).

__________________
This message is hidden because Forgery, Honda Racer, JackBoot, LawnGuyLandSparky, milehiwire and user 5941 are on your ignore list.

jtomara37

yes permit has been pulled. Sorry if my lack of experience in commercial industrial work falls short of your expectations. believe me when I say I was surprised when I got my master's licence 9 yrs ago. Most of my brain cells were fried back then still trying to recover. Since then I have been an idiot residential old work construction, electrician. Code book... rarely used or needed to use since my licence.

jtomara37

480sparky

1. #10
2. Was thinking about the cooler unit I also would have to wire that is also 3 phase along with potential lights that had not been decided yet. Thoughts were not completely formed when I wrote my questions
3. The basement of this tiny dinner restaurant is horrific. I really don't want to go into too much details about it. The deal is it will be alot simplier if I run Mc instead of doing emt. never mind stupid question
5. I never had to buy 10-3 MC so wasnt sure if they made it (although this is a lie now that I think of it I have seen it before.. writing 10-4 was a typo. was slightly confused with buying Cord where 10-4 would include ground where 10-3 mc would be white,black,red,green.. whatever dismiss
6. Bonding bushings I had seen and been exlplained to me several times but because I never actually had the need to retain this information I figured I'd ask again just in case.


Tried to save myself some time to get some quick answers on a forum cause I'd never done this before.. apparently I am unwelcomed hence the serious sarcastic remarks i got from you guys. back to sticking my nose in a book i suppose

480sparky

It isnt that you're not welcome, but these sounded more like test questions. I realize you are actually doing the work, but you should not be asking questions of this caliber with what appears to be lack of experience. True, no one knows everything, but it sounds like you're in over your head on this one.

But to answer your original questions:

1. #10.
2. If you even spliced four #10s, you could use a 4x4x2-1/8. That box can have a dozen 10s in it. Or a 4-11/16 box would work as well (T314.16(A)).
3. I don't think there's a case in the NEC that disallows splices in a branch circuit.
4. Color would be your choice, just not white, grey, green or green with one or more yellow stripes. Black/red/blue is an unofficial standard for 120/208. If you have 480, typically brown/orange/yellow is used.
5. 10-4 MC is available, but the supply house may not sell it by the foot, so you'd have to buy the whole roll. If it had red/black/white/green, you could remark the white with blue tape and be legal. If you go with flex, you need to be neat and keep it straight.... you are still only allowed 360° of bends (348.26).
6. Bonding bushings would not be required.
7. A 'knife switch' would work, as long as it is rated for 30 amps and in a NEMA 3R case if it's outside.

As for running a neutral along with the 3 phases for lights, you should run a seperate circuit for that instead.

Again, don't take our comments as meaning we're taking in the Welcome mat... you ARE welcome here, and realize that there are no stupid questions.

__________________
This message is hidden because Forgery, Honda Racer, JackBoot, LawnGuyLandSparky, milehiwire and user 5941 are on your ignore list.

rlc3854

Don,t take the replys as unwelcomed. The replys are based on not wanting the liablity of having the information to help someone fry themselves and take work from licensed professionals. The other reply was one that would be helpful for someone like you to become reaccuannied with the code and commerical work,systems and materials. You have experience and a niche, how many times have you been on jobs and other home owners come ask questions of what and how to do something? Only to know that they will attempt the work themselves and have no inttention of hiring you? Just saw 480's post, you did say 120/240 3 phase correct? Be aware of the high leg of this system typiclly "B" phase, colors for this is black-orange-blue.

micromind

Nevermind, ric3854 beat me to it. (High leg marking).

Speedy Petey

jtomara, I see you are all over the web with this quest. I have to say, I tend to agree with RK, in theory.
True, we all stated out knowing nothing, but most of us either had good folks we worked under, or learned this stuff as much as possible before going at it. This type of job is NOT a place to learn as you go.

I made a reply similar to 480's on the ContractorTalk site.
I will NOT give answers to all these questions, but I will help you find the answers yourself.



I do NOT take this statement very well at all. I truly hope you are not serious.
Do you think the code is just something you learn to pass a test and then forget it, like 9th grade history?

480sparky

Oops, I missed the 120/240 thing..... I rarely see it here. I'm used to 120/208.

__________________
This message is hidden because Forgery, Honda Racer, JackBoot, LawnGuyLandSparky, milehiwire and user 5941 are on your ignore list.

scrooge

480 official brown,yellow,purple.

scrooge

boy ok with me tho.

Speedy Petey

"Official" to whom? I have never even seen that combo.
All I have ever seen is B-O-Y.

480sparky

Same here.... BOY all day long.

Purple to me means Travellers.

"Official" must mean some local code.....

__________________
This message is hidden because Forgery, Honda Racer, JackBoot, LawnGuyLandSparky, milehiwire and user 5941 are on your ignore list.

simmo

It's interesting to see the diffferent colour code standards from different parts of the world. I cannot believe we still don't see a common ISO Standard that is world-wide. In Australia and New Zealand Phase wires in a 3 phase is Red, White, Blue and Nuetral been black - Something I would have thought America would have at least adapted to, been the Patriot Colours as shown on your flag.

MechanicalDVR

Hope it helps you out. Good luck with growing those brain cells back, sometimes you have to put the romex down and step away from the resi.

scrooge

nec 215.8.I agree boy most used for 480.OK with me.Is there pink in Sydney?

480sparky

There is no 215.8....

__________________
This message is hidden because Forgery, Honda Racer, JackBoot, LawnGuyLandSparky, milehiwire and user 5941 are on your ignore list.

HighWirey

480,
Thank you for the endorsement.

Want a hoot?

Once did a project known as the "Lithium Battery Storage Facility". Evidently the government wanted to keep their batteries really chilled (<5Degrees F). I was a pup, and did not know about sealing incoming conduits against intruding moisture. Talk about your icicles!

Guess that is what experience is made of, huh?

Best Wishes Everyone

__________________
Be Safe Out there

HighWirey

480,

I beg to differ . . . there is a 215.8, titled "Means of Identifying Conductor with the Higher Voltage to Ground". I admit it is in my oldtimers 1999 version of Funk and Wagnels . . .

Should have checked before my last post, but that beeg hardback makes my head hurt . . .

Best Wishes Everyone

__________________
Be Safe Out there