[DanS26]

I am installing a 10kW permanent mount generator which will feed a 12 position automatic transfer switch. My main distribution panel is a 24 circuit panel and is maxed out. It is quite crowded in the panel. I think by adding the transfer switch wiring it will make the panel too crowded and may exceed the panel fill guidelines. All those wire nut connections in there will just make for a messy panel.

What I would like to do is to install a large junction box ahead of the transfer switch which will house the backup circuit connections and thus keep them out of the main distribution panel. I have seen large Carlon junction boxes that may be large enough for 12 circuits. It measures 12"x12"x6".

My questions are:

1. Is the junction box large enough?
2. What type of connections would be appropriate and code approved other than wire nuts? I'd like to keep it neat.
3. Are there other better methods to create these pass through circuit connections?

Thanks, Dan

 

[stickboy1375]

........................

 

[DanS26]

Well, thanks everyone for all your help!!!:whistling2:

I guess I'll dive deeper in my own search or else find another site to ask.

So far I'm leaning on installing a Feed Through Terminal Block rated for 30+ amps/ 600V each block that is mounted on a DIN rail inside of a large junction box.

Any electricians here have experience with that type of installation. Pros? Cons?

Dan

 

[darren]

Would you not have a new emergency panel with your critical loads in it.

Thus you would have a main panel with your non critical loads, from this panel you would feed your transfer switch and then on to your emergency panel.

Under normal operations your emergency panel would run of your main panel which is run from the electrical grid. During a power loss your generator would kick in and let your emergency panel to work.

 

[DanS26]

Would you not have a new emergency panel with your critical loads in it.

Thus you would have a main panel with your non critical loads, from this panel you would feed your transfer switch and then on to your emergency panel.

Under normal operations your emergency panel would run of your main panel which is run from the electrical grid. During a power loss your generator would kick in and let your emergency panel to work.

The problem is that my critical load lines are not long enough to be wired directly into the emergency panel. Thus the need for a junction box to extend the line lengths.

I noticed you are in Canada and I think I read somewhere that the Canadian codes do not allow for the wire nutting in the main distribution panel. So the Canadians must deal with this issue on a regular basis.

 

[darren]

I have heard that we are not suppose to but i don't know the code reference for it.

Could you not put your new emergency panel right next to the main panel and swap which lines you need over to the emergency panel.

If you can't there is no reason you couldn't mount a junction box at the main panel and take what you need out of that panel and extend the lines for they reach. You wouldn't need a huge junction box, maybe a 4 11/16x 4 11/16 or at worse a 6x6.

 

[DanS26]

I have heard that we are not suppose to but i don't know the code reference for it.

Could you not put your new emergency panel right next to the main panel and swap which lines you need over to the emergency panel.

If you can't there is no reason you couldn't mount a junction box at the main panel and take what you need out of that panel and extend the lines for they reach. You wouldn't need a huge junction box, maybe a 4 11/16x 4 11/16 or at worse a 6x6.

I'd give you a code reference, but I have a hard enough time with the NEC. Don't get me wrong, I think the NEC has save countless lives and for the most part has done a great job of protecting us all.

Maybe two or three of the 12 circuits are long enough to move directly from the main panel to the emergency panel. All the rest will have to be lengthened. I think the feed through terminal blocks will make for a simple and neat junction box arrangement without all the wire nuts going everywhere. I calculate that I will need 22 blocks in the junction box on one DIN rail to move the 12 circuits since one of the circuits is 240v. Plus about a 15 hole ground bar kit, but if I put the kit in the emergency panel I will need an additional 12 blocks for the grounds.

I think you are right, probably need a box around 6x6 but will probably go with a larger box just to give me room to work. Thanks for your input.

 

[stickboy1375]

I think its a shame you have a 10 kw generator and are only getting 12 circuits out of it...


If this were my set up, I would see what that ATS is actually rated for and then feed a sub-panel with the maximum size wire that the ATS could handle... to give you more options for that monster generator... 12 circuits will most likely be a waste for that size generator.

 

[k_buz]

The JBox will be fine. I would not bother with anything other than wirenuts, its just not worth it. Remember that the neutrals have to go to the generator panel as well. You cannot just move the "hot" wires.

 

[DanS26]

I think its a shame you have a 10 kw generator and are only getting 12 circuits out of it...


If this were my set up, I would see what that ATS is actually rated for and then feed a sub-panel with the maximum size wire that the ATS could handle... to give you more options for that monster generator... 12 circuits will most likely be a waste for that size generator.

The reason for the 10kW generator is that I want to start up a 2 1/2 ton whole house AC. My normal load for the entire house is 800w to 2500w, but the AC will kick up loads to 10,000w but run at around 3,000 to 4,000 watts on top of the normal loads. Yes, we pay for comfort, but when mama is happy everyone is happy and vice versa of course.

I use a TED system so I know EXACTLY what I use every minute of the day and night.

 

[DanS26]

The JBox will be fine. I would not bother with anything other than wirenuts, its just not worth it. Remember that the neutrals have to go to the generator panel as well. You cannot just move the "hot" wires.

Yes, that's why I need 22 feed through blocks. 12 for the hots and 10 for the neutrals. You're right, wire nuts are code compliant and cheap, but I like neat. I'll pay extra for neat, its just the way I am.

 

[Speedy Petey]

How are wire nuts not neat?

I get the impression you are looking for OCD, not neat.

 

[k_buz]

How are wire nuts not neat?

I get the impression you are looking for OCD, not neat.

Like this?

 

[Missouri Bound]

I use a TED system so I know EXACTLY what I use every minute of the day and night.

Does the word "anal" seem to apply? :whistling2:

 

[tylernt]

Once I learned what an interlock was and what it did, I can't imagine why anyone would bother with a piddly little transfer switch.

Especially for a 10kW permanent generator!

 

[AllanJ]

You would not need that many wire nuts in the breaker panel.

For each critical circuit, a pair of wires comes from the transfer switch unit into the panel, one attached directly to the panel breaker for that circuit and the other wire nutted to the circuit conductor that was just taken off of that breaker. If the wires from the transfer switch unit are not long enough then go ahead and mount a junction box just outside the panel to splice on extensions, or, you could replace the wires coming out of the transfer switch unit with new longer wires.

If you take some of the branch circuit cables out of the panel and attach them to the junction box then individual neutrals must continue on into the panel. One ground wire, sized for the largest branch circuit moved to the junction box, connects the new ground bus in the junction box to the ground bus in the panel.

 

[Speedy Petey]

Once I learned what an interlock was and what it did, I can't imagine why anyone would bother with a piddly little transfer switch.

Especially for a 10kW permanent generator!

Standby automatic generators, like the OP has, REQUIRE piddly little transfer switches. :whistling2:

 

[DanS26]

Thanks everyone for your advice, especially AllanJ for his advice on the grounding.

Dan

 

[DanS26]

Just wanted to update this thread with the progress on the Junction Box project. I obtained a 8x8x4 Carlon junction box and mounted 22 pass through blocks rated for 30 amps each at 600V. Also mounted a ground bar as required. As you can see I numbered the circuits. Only 1 and 3 are 30 amp, the rest are either 15 or 20 amp.

I mounted the box, which now is ready to make the transition of the critical circuits from the main distribution panel. 11 circuits will be transferred.

Thanks for everyone for your helpful comments.

 

[tylernt]

Is combustible material like wood allowed in a JB?