This question is in regard to Class 2 and 3 circuits according to the US
National Electrical Code.
Reference note 2 in Table 11(a)., Class 2 and Class 3 Alternating-Current
Power Source Limitations which says, "For nonsinusoidal ac, Vmax shall not
be greater than 42.4 volts peak. Where wet contact (immersion not included)
is likely to occur, Class 3 wiring methods shall be used or Vmax shall not
be greater than 15 volts for sinusoidal ac and 21.2 volts peak for
nonsinusoidal ac."
The Code has a clear definition of a wet location, but there is no
definition of "immersion". The code is clear that a concrete slab at ground
level is considered to be a wet location. Any non-water tight conduit
installed in the slab would also be considered to be a wet location (my
interepatation).
We now have an electrical inspector in Florida stating that such a conduit
location is an "immersion" area since it is well known that water will be
present. Therefore; this must be taken into consideration when classifying
the circuits Class 2 or 3 and using the proper cables.
Has anyone else run into this interpretation?
Richard Woods
Richard Woods
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