On Chol Hamoed, the work being allowed is a function of whether it is done by an commoner or expert.
On Shabbos that does not matter what kind of person does the work in skill level..
Does anyone explain this?
Chaim Schild, USA
1. Some Rishonim (including the Rambam, Hilchos Yom Tov 7:1) maintain that the prohibition against working on Chol ha'Mo'ed is mid'Rabanan. According to this view, we can understand that for Tzorchei ha'Mo'ed -- things which are needed for Chol ha'Mo'ed, which is part of Yom Tov and there is a Mitzvah to be happy -- Chazal permitted doing work which does not require an expert, since this does not make Chol ha'Mo'ed similar to a weekday. However, if there is no need for this Melachah on Chol ha'Mo'ed, a commoner's work is also prohibited, as the Beis Yosef writes (Orach Chayim 541, end of DH Mesargin): "If there is no need for this on Chol ha'Mo'ed, why should Chazal permit any work even if it is non-expert?"
2. However, many Rishonim maintain that the general prohibition on Chol ha'Mo'ed is mid'Oraisa; see Tosfos to Chagigah 18a, DH Cholo, and Bi'ur Halachah OC 530 DH u'Mutar. According to this view, we can explain based on the Gemara (Chagigah 18a) which states that the Torah handed over to Chazal the authority to decide which work is prohibited on Chol ha'Mo'ed and which work is permitted. According to this, we also can understand that Chazal said that in order to help people perform the Mitzvah of Simchah on Chol ha'Mo'ed, non-expert Melachos are permitted on Chol ha'Mo'ed.
Kol Tuv,
Dovid Bloom