p.80 of “Electrical Safety for Live Events” by Marco van Beek has an interesting case study. Given the book is UK based so it’s of limited use for terms and technology used in the Us, but it does have some good information to supplement better US based texts. In the case of PAR 64 lamps, even if 230v power supplies, often they will use 120v lamps and 28v ACL lamps just as we do here. In their case, they are using both lamps in series as opposed to here we would just be doing the ACL lamps in series. Four 28v ACL lamps in series equals 112v at 1,000 watts when supplied by a 110-125v service. This as opposed to eight of them in the UK or two 120v lamps for 230v based systems. So in the study it was found that for some reason when a 28v/250w ACL was stuck in series with a 120v/1,000w lamp on a 230v system, the 120v/1Kw lamp would blow first. Why is this? No cheating.