is a great site for helping with your home games
They have Roberts Rules and TDA Rules as well as their own HPT rule book, where I found this in the Betting and Raising section:-
3. In no-limit and pot-limit games, unlimited raising is allowed.
4. In limit poker, for a pot involving three or more players who are not all-in, these limits on raises apply:
(a) A game with three or more betting rounds allows a maximum of a bet and three raises.
(b) A game with two betting rounds (such as lowball or draw) allows a maximum of a bet and four raises. [See “Section
16 - Explanations,” discussion #6, for more information on this rule.]
5. Unlimited raising is allowed in heads-up play except in tournaments. This applies any time the action becomes heads-up
before the raising has been capped. Once the raising is capped on a betting round, it cannot be uncapped by a subsequent
fold that leaves two players heads-up. (For tournament play in limit events there will be a limit to raises even when
heads-up until the tournament is down to two players.)