Yes it is permissible as long as you continue to use the max amount of conductor’s permitted for the size of the Marr. you are using.
JUST A NOTE;
When twisting a 12awg CU stranded with a 12awg AL or #14awg AL conductor that is solid or stranded the inspectors in the lower mainland espy Vancouver and Burnaby are now looking more closely for a “PURPLE” colored Marr in these cases as they (ALL SIZES), have a better HYDRO type anti-corrosion compound un like PENETROX or NOALOX in them and bursts into the wires thoroughly when twisted.
Robert Wagner.
