Wire too small for main lugs in panel

[rexp2]

I have a Siemens Series E main lug panel that I want to use as a sub panel. It will be located next to the main panel. I plan to use a 50 A circuit breaker in the main panel with 6 AWG wire connecting to the sub panel. The problem is that the main lugs on the sub panel are rated for #4-2/0 AWG. How do I up size the wire to fit the lugs? I have not found any smaller gage lugs for this panel. Alternatively, I could back feed the sub panel using a 50 A double pole circuit breaker but this requires a hold down strap which I have not been able to source. Thank you for your help.

 

[Little Bill]

I am closing this thread in accordance with forum rules. This forum is intended for use by electricians and electrical contractors, inspectors, engineers, and vendors with their job-related duties. We are not allowed to provide how-to advice to persons who are not employed in this industry, or persons who do not perform electrical installation or maintenance as part of their jobs. Engineers are welcome to participate, but only if their questions do not involve attempts to perform their own electrical installation, troubleshooting, or maintenance work.

If I have misread the situation, if for example you have an electrical contractor on board to perform the installation work, then send me a PM to explain the circumstances.