What is the problem?
In order to test SecurePoll on beta, some users will need to be in the electionadmin group so they can edit and administer elections.
Some users will probably also need to be in the electcomm group, so they can create elections and add users to the electionadmin group.
See https://vote.wikimedia.org/wiki/Special:ListGroupRights#electcomm and https://vote.wikimedia.org/wiki/Special:ListGroupRights#electionadmin. Beta probably wants to replicate votewiki as close as possible.
I suspect most testing will be on https://en.wikipedia.beta.wmflabs.org, but if we can get it on all the beta sites that wouldn't hurt.