Splicing inside service panels and sub panels question???

[jango]

I have a situation where a friend of mine wants to add what he calls a "critical load sub panel" which will be fed by a battery back-up system via his solar company. They are bringing over a battery back up set up which they say is rated at 40 amps @ 120V. I need to bring six existing circuits into the new "critical load sub panel". Three of the existing circuits originate from the meter/main/load service panel and the other three existing circuits come from a different sub panel. I have two questions: Am I allowed to splice inside the service panel and the sub panel to extend these six circuits to the new "critical load sub panel"? And if so, is there a particular type of connector that needs to be used for the splicing? Also, the fact that the "critical load sub panel" is fed at 120V can I install a jumper between to two critical load sub panel input lugs so I have 120V on both legs of the busbar? Or is there a specific type of sub panel unit to be used in this situation that is only fed with 120V? Any input on all of this would be greatly appreciated.

 

[tom baker]

Splicing is allowed as long as you dont excce 75% of cross sectional area for spliced and 40 % for wire. I dont have code bok handy to give you sections.
any type of listed wire connector is allowed, ie a wite nut.
For the panel. I have done what you ask, cant recall a rule against it, but you cant connect any 240 loads.

 

[LarryFine]

Actually, the one flaw in this plan is jumping the panel lugs. Use a wire-nut or a 3-hole bus-bar and two pigtails to get around it.

 

[synchro]

The neutral bar on the new panel will need to supply the total current draw of all 6 circuits, even though the the 120V phase current is split between two buses. It's probably not a problem, but it should be kept in mind when selecting the panel.
Also if some of the 6 circuits are part of a multi-wire branch circuit then the neutral may be subject to overloading when all circuits are driven with the same phase.

 

[jango]

Thanks everyone!:thumbsup:

 

[JoeNorm]

I would confirm that the backup will only be 120V. We do a lot of this and always supply the the "backed up loads" with 240V