wiring a branch circuit????

[Cajy Ohone]

I have grouped the ends of 8 each 12-2 w/ground wires in the center of my attic that feed various 15amp receptacles (the longest wire being less than 20' in length).

My questions are:

1- What gauge main wire will I need to feed feed these wires from the breaker box that is less than 20' away?
2- What amperage breaker will I need?
3- What type of junction box is required to connect the larger gauge wire to the 12-2 wires?

Thank you in advance for any info

[Michael Larson]

20 A breaker max.

You have to protect the 12 gauge wire and it is only rated for 20 A.

You have a larger problem with the size of the junction box and the wire nuts needed to connect it all.

Each junction box is rated for a maxim number of conductors and wire nut connections.

314.16 Number of Conductors in Outlet, Device and Junction Boxes, and Conduit Bodies

Boxes and conduit bodies must be of sufficient size to provide free space for all enclosed conductors (See Figure 2). The term “free space” should not be confused with “free conductor” located in 300.14. Contrary to the opinion of some electricians, there are requirements that limit the number of conductors allowed within outlet, device, pull and junction boxes. Many times, when covers are removed from junction boxes, it is discovered that the box is packed full of conductors, and no consideration was given to the sizes and numbers of conductors. Disregarding box fill requirements can create safety as well as fire hazards (See Figure 3).

Article 314 contains detailed requirements for box fill and junction box sizing. Two sections refer to box fill calculations: 314.16(A) Box Volume Calculations, and 314.16(B) Box Fill Calculations. In no case shall the volume of the box, as calculated in 314.16(A), be less than the fill calculation as determined in 314.16(B). Requirements for calculating the minimum volume for conduit bodies are located in 314.16(C). Conduit bodies, also referred to as condulets, are manufactured with a variety of configurations. The Type (i.e., LB, LR, LL, C, T, etc.) indicates the number and location of conduit entries. Unlike junction boxes and conduit bodies, terminal housings supplied with motors are not required to meet box fill requirements.

Use 314.16 to determine the size box required for conductors 18 AWG through 6 AWG. These boxes are calculated by using the number of conductors and their respective sizes. Boxes and conduit bodies enclosing conductors 4 AWG or larger must also comply with the provisions of 314.28.

314.16(A) Box Volume Calculations

Various sizes of metal boxes are listed in Table 314.16(A).

[Cajy Ohone]

Isn't there a junction box available with a bus bar that I can use?
I also understand that I don't ground this secondary box?

[Cajy Ohone]

any idea what size wire I need to feed the junc box?

[KEVIN WOOD]

Agreed! You should call in a electrician for this work if you don't have this info.

[Cajy Ohone]

can't afford one if there is someone here knowledgeable with the facts I've stated.
Should be fairly straight up info??

[Michael Larson]

You are not understanding something.

The 12 gauge wire MUST be protected by no more than 20A protection.

Hire or find someone who understands before you hurt someone.

[Jeffrey R. Pope]

Originally Posted by Cajy Ohone

I also understand that I don't ground this secondary box?

EVERY metal box must be bonded to the GES.

[Cajy Ohone]

OK thanks for the info.

[Jeffrey R. Jonas]

Why am I envisioning multiple pigtails in that proposed box?

I hate to say this, but I hope that is his home, and not that of an innocent!!

[Robert J. OConnor]

If you dont have the money to hire a professional, dont run the circuits. You likely will just end up hurting someone.

[Linas Dapkus]

Don't forget the duct tape.

[Cajy Ohone]

Thank you again Mr. Larson and Mr. Pope for the useful information.

[Robert Meier]

Originally Posted by Cajy Ohone

I have grouped the ends of 8 each 12-2 w/ground wires in the center of my attic that feed various 15amp receptacles (the longest wire being less than 20' in length).

My questions are:

1- What gauge main wire will I need to feed feed these wires from the breaker box that is less than 20' away?
2- What amperage breaker will I need?
3- What type of junction box is required to connect the larger gauge wire to the 12-2 wires?

Thank you in advance for any info

Sorry guy but you're in over your head. You're looking to run a larger conductor/cable with larger than 20 amp OCPD to this box and then splice onto your 12/2 circuits. This would involve tap rules and other stuff that is way beyond the scope of this forum.

[Cajy Ohone]

To maintain the professionalism of this site I took the liberty of reporting the unnecessary posts such as "I hate to say this, but I hope that is his home, and not that of an innocent!!" and "Don't forget the duct tape". These could be construed as "Taunting" as described in the site rules. The duct tape comment was obviously made to ridicule but the "I hate to say" comment was a direct afront to the safety of myself and my family directed to other than the initiator of the thread.