Right way to connect #2 and #6 in line?

Mud

Diamond

Joined

May 20, 2002

Location

South Central PA

• Feb 4, 2020

• #1

I currently have a transformer supplied with 240 and feeding a machine with 480. AWG 2 input, AWG 6 output. I'd like to take the transformer out of the circuit and have 240 coming out of the #6 cable. I don't want to undo all the conduit and disconnect and etc, I just want to connect the 2 cables and leave the transformer mounted up on the wall where it is in case it's needed later, without it drawing any current now,

What's an NEC compliant way to connect the wires? I've seen this done with lugs and huge gobs of tape, is there a nicer way?

 

D

DDoug

Diamond

Joined

Oct 18, 2005

Location

NW Pa

• Feb 4, 2020

• #2

A short (but large studs 1/4" or so) terminal strip ?

 

I

Impractical

Aluminum

Joined

Jun 14, 2011

Location

Kansas, USA

• Feb 4, 2020

• #3

Google "Insulated Mechanical Lug". These are available from Ilsco, Burndy, and others. They will accept a wide range of wire sizes in each "port". For example, #14 - 1/0 would probably work well. Since these are insulated, you avoid the "huge gobs of tape". Electricians around here often refer to these as polaris lugs.

Here's a Burndy link...

Insulated Mechanical | Mechanical Connectors and Terminals | Electrical & Electronic | Products | Burndy

Disclaimer: I'm not an electrician, so can't speak with authority regarding the code-worthiness of this.

 

I

Impractical

Aluminum

Joined

Jun 14, 2011

Location

Kansas, USA

• Feb 4, 2020

• #4

Also, you might need to switch to a smaller breaker to protect the 6 AWG wire.

 

SAF

Stainless

Joined

Jul 20, 2014

Location

MI USA

• Feb 5, 2020

• #5

Right way to connect #2 and #6 in line?

Click to expand...

The right way would be to run your #2 to a small 3Φ loadcenter, then provide the proper breaker to feed your #6 and one to feed your transformer when needed. It won't cost much more for the materials to do it right, than the insulated mechanical connectors.

3Φ Loadcenter

60A 3Pole Breaker

If you want to keep it simple and unprotected, and a pain to switch over, look here.

Manufacturer of Aluminum and Copper set screw connectors for the Utility, OEM, and Contractor and Industrial Markets

Insulated Mechanical

SAF Ω

 

Mud

Diamond

Joined

May 20, 2002

Location

South Central PA

• Feb 5, 2020

• #6

Thanks. I already had a 60A breaker ready to install. I'm looking through my stuff for a 60A disconnect to install at the transformer location, I can see that would be better. The machine on the end will have 60A fuses at the line connection/disconnect switch. The #2 wire is THHN, the #6 is S cord.

Why are 60A fuses and breakers OK on #6 wire, when the ampacity of #6 is listed on most charts that I've found at 55A?

 

R

Rob F.

Diamond

Joined

Aug 5, 2012

Location

California, Central Coast

• Feb 5, 2020

• #7

I heard once that loose wires in conduit can handle more amps than cord because they cool easier. (or dont give each other their heat)

 

SAF

Stainless

Joined

Jul 20, 2014

Location

MI USA

• Feb 5, 2020

• #8

Mud said:

Thanks. I already had a 60A breaker ready to install. I'm looking through my stuff for a 60A disconnect to install at the transformer location, I can see that would be better. The machine on the end will have 60A fuses at the line connection/disconnect switch. The #2 wire is THHN, the #6 is S cord.

Why are 60A fuses and breakers OK on #6 wire, when the ampacity of #6 is listed on most charts that I've found at 55A?

Click to expand...

The answer depends on the installed conditions and wire type. Circuits of less than 100A are to use the 75C temp column, unless all connections are approved for a higher temperature.

Table for building wire.


Table for Cords.


SAF Ω

 

plastikdreams

Diamond

Joined

May 31, 2011

Location

upstate nj

• Feb 5, 2020

• #9

Electrical tape with a few wraps of linemens tape...get the good stuff that's rated 69kv...and do it nice