[tech2480]

Hello all,

I want to apologize in advance because I have a few questions to ask so this may get a little long. The building that I'm working on is going to be my home for me and my family and it was zoned commercial so that makes things a little more complex. So let's dive right in...

1- This is being considered a new construction project by the city so all of my breakers need to be changed over to AFCI if need be... that said I looked on the package the other day and read that they can't be used if you have shared neutral circuits. Given how they need to be installed, I understand that. I quote, "This arc-fault detection device is not designed or intended for use on circuits in which the neutral conductor is shared with other circuits. The circuit breaker will nuisance trip in "shared neutral" circuits." (From Square D's instruction manual) However, are there AFCI's made to work with shared neutrals? Or am I going to have to have neutrals to some of my circuits? Also, how many 12 gauge wires can be in a 1/2" EMT?

2- I need to install my subpanel out in my attached garage to power up the laundry room and garage circuits and given how everything is laid out it looks like I can only put it facing the garage area not the laundry room. Is there anything that says I can't have the access to the panel in the garage? And if not how high off the ground should it be?

Thank you in advance.

[donf]

To start, I would strongly recommend that you contact several licensed electricians to bid on correctly sizing the needed residential load as well as bidding on the work itself.

Also, normally, renovations less than 60% are not required to re-do the electrical. Just how much of a tear down and renovate of a job are you doing?

(P.S.) Just an after thought, do you know what a shared neutral means and how it is wired? An AFCI breaker cannot be used on a shared Neutral. End of discussion.

NEC 2008, Chapter 2, Article 210.12 (B) – “Dwelling Unit Circuits”

All 15A or 20A 120V branch circuits supplying outlets in family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, or similar rooms or areas shall be protected by a listed AFCI device of the combination type.

AFCI breakers are built to monitor the branch circuit for the electrical signature of an arc. Arcs cause fire.

[donf]

A Sub-panel is an entirely different topic.

To begin with, you need to do a load calculation for the panel in the garage.

Next, you need to size the cable from the main panel to the garage.

Since you are bringing electrical power to the garage, your garage must have a light mounted on the outside of the entry door.

Next, outlets need to be GFCI protected.

The feed from the main service panel must be a four wire feed. The garage will need its own grounding system tied to one or two ground rods (as needed). The ground and Neutral terminals MUST be isolated from each other.

And much more.

[tech2480]

A Sub-panel is an entirely different topic.

To begin with, you need to do a load calculation for the panel in the garage.

Next, you need to size the cable from the main panel to the garage.

Since you are bringing electrical power to the garage, your garage must have a light mounted on the outside of the entry door.

Next, outlets need to be GFCI protected.

The feed from the main service panel must be a four wire feed. The garage will need its own grounding system tied to one or two ground rods (as needed). The ground and Neutral terminals MUST be isolated from each other.

And much more.

No disrespect intended but none of that answers my original posted question. All of the above have been checked, re-checked, and checked again. I am not a professional electrician by any means but that doesn't mean that I'm not new to the craft! I do however thoroughly appreciate the time and consideration that you put into your answer i.e you need to do baby steps before you can walk and I'm fully aware of that. So that being said and with all things moving forward... does anyone have an answer to said question?

[tech2480]

And for giggles I'll give answers to the above...

100 Amp service
2-2-2 aluminum service

[tech2480]

To start, I would strongly recommend that you contact several licensed electricians to bid on correctly sizing the needed residential load as well as bidding on the work itself.

Also, normally, renovations less than 60% are not required to re-do the electrical. Just how much of a tear down and renovate of a job are you doing?

(P.S.) Just an after thought, do you know what a shared neutral means and how it is wired? An AFCI breaker cannot be used on a shared Neutral. End of discussion.

NEC 2008, Chapter 2, Article 210.12 (B) – “Dwelling Unit Circuits”

All 15A or 20A 120V branch circuits supplying outlets in family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, or similar rooms or areas shall be protected by a listed AFCI device of the combination type.

AFCI breakers are built to monitor the branch circuit for the electrical signature of an arc. Arcs cause fire.

Not that it should matter to the question but all of the existing wiring was done in conduit and I've basically branched off the existing junctions in the crawlspace (single story dwelling). All of the conduit and wiring from the subfloor on up has been removed. The footprint of the structure is the same but the space has been laid out differently i.e. bedrooms, baths, kitchen, etc. None of that matters because the city has defined the property as new construction and is stated on my permit.

As far as the shared neutral portion of it is concerned... my definition would be that the hot portions of two circuits share a neutral wire.
Nevertheless it sounds like I'm going to be adding neutrals to the system... Thanks for your help!

[donf]

Tech,

I was not trying to be offensive, sorry if I was.

I'm sitting here in Virginia Beach, VA with absolutely no idea what is physically in front of you.

I have no idea of your skill level nor your knowledge of the NEC code.

Should I guess or just assume you know what you are doing. Keeping in mind that a false assumption on my part can get you killed.

As to the percentage of reconstruction, I was just curious.

If yo are going from basically bare walls, then absolutley this is a new construction.

You are correct on your definition of shared neutrals. However, for some circuits that is fine. Case in point the 2 required 20A circuits for the Kitchen counter tops. These can be run off a shared neutral, at least I believe they can. I'll know for sure as soon as I get home and go through my code book.

[KISS]

There is a Sticky in this section which shows you how to read the NEC code online. You can't print or search, but you can read.

You'll have to look at the section on conduit fill and de-rating.

[tech2480]

Donf,

True enough... I guess I should have kept my panties on a little while longer before I made my last post... I apologize! It's been a rough day!

I forget that in the internet world you can only describe so much and to as much detail as I write in these posts!

And as far as level of construction, I probably should have stated those things from the start... as it probably would have helped...

Thanks again!

KISS,

Thank you I'll have to check that out, I read today elsewhere that you can put up to six in the same 1/2" stick of EMT.

[Missouri Bound]

TEch... look for the "Ugly's" book online for electrical work. It's about 10 bucks and has tables and general information for electrical work. As far as the panel in the garage, no problem as long as clearance is maintained in front of the panel. And depending on the type of wire, you could put up to 9 wires in 1/2 emt. (but I wouldn't want to pull that many) Check out the book and good luck.

[donf]

Tech,

I took a moment to look up your service conductors. #2 AWG AL conductors are appropriate for “Service” conductors based on table 310.15 (B)(6) of the NEC.

However, if you are referring to the feeder to the garage, then table 310.16 must be used.

This table shows that at 60c 100 amps would need #1/0 AL AWG. At 75c #1 AL AWG needs to be used.

Most devices in the U.S. are listed for both 60c and 75c. #2 AWG AL can only be used to carry 100 amps to a 90c listed connection and those are special order configurations.

Take a moment and look at the sub-panel box and see what the listed temp is. I believe it will be 60/75.