I think that the nec does allow for this type of instalation, as in 210-21 3. it does say "supplying two or more"
210-21. Outlet Devices
3. Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the values listed in Table 210-21(b)(3), or, where larger than 50 amperes, the receptacle rating shall not be less than the branch-circuit rating.
Exception: Receptacles for one or more cord- and plug-connected arc welders shall be permitted to have ampere ratings not less than the minimum branch-circuit conductor ampacity permitted by Sections 630-11(a) or (b) as applicable for arc welders.
Table 210-21(b)(3). Receptacle Ratings for Various Size Circuits
Circuit Rating
(Amperes) Receptacle Rating
(Amperes)
15 Not over 15
20 15 or 20
30 30
40 40 or 50
50 50
:Wayne
