Working on a remodel and need about 5 more circuits than the panel will except (40 space 40 circuit homeline). Told customer my plan to put a main lug right next to it to accommodate extras, but for whatever reason he wants an identical 40/40 panel placed next to it (for astetics, I guess). Never placed a mnin panel next to another one. Do I jump inputs from lug to lug or just take out a 2 pole and jump to new panel and put like a 60 amp main breaker in , don't see mee needing much amperage in new panel. Can I just jump grounds from panel to panel. Any help would be much appreciated. Thanks

Are you seriously asking this?
I'd like to suggest you let a professional who knows the proper codes and practices handle things like this.
If you are getting paid for jobs like this and have to ask such questions you should not be doing the work.

That's why I'm asking to see if its something I could do. I'm certainly not going to put customer at risk. And judging by your reply I guess I'll do just that. And thank you for your help.

brundlefly4...
Have you done this kind of work before? Your question, as elementary as it is makes me think that you are not an electrician but perhaps a contractor. Although some of the NEC rules are vague and often redundant, every panel needs to be protected in some way for overload. Think about what you are asking. Iknow that this is the "ask me" help desk but often, when one of the professionals here think that you are over your head will tell you so, rather than lead you down a path which could be dangerous to you or others. Information is a dangerous thing in the wrong hands.

There was a method to my madness in asking that question. I am competent with residential electric. stanfortyman's answer was more than I had hoped for in persauding my homeowowner, no matter how insistant I was that putting in an identical panel just wasn't feasible (especially a 40/40) where I tried to explain he'd be so out of code, not to mention he'd have 35 unused slots. So between the cost differance(which carried little weight with him), stanforty's response and my insistant response that I can't do it , he finally relented and I'm putting in a main lug. And the kicker in all this is that its in his (albeit spotless) garage. Go figure. Must be nice to be wealthly and usually get what you want. In case your wondering, the main breaker only has 3- 2 pole c.b. in so I'm good to feed sub. Thanks again for your responses. Appreciate and respect you guys and what you have to say. Especially when it comes to keeping us safe.

brundle,
You never mentioned if you were licensed to do electrical work...
If you're not, you should be aware that you are accepting a tremendous liability.
permits, inspections and contracts keep professionals from having their life sued out
from beneath them.
I sincerely hope you are licensed and performing this work legally.