[PVRCNC] 12AWG =30 amp?

[alsopb]

Guys,

Ran across something odd while planning the install of a programmable 
timer for hot water heater.  Looking for comments.

1) Circuit breaker box shows dual 30 amp breakers (well not quite--see 
below)
2) Heater element rating 4.5Kw (19 amps).
3) Wire gauge at heater = #12

This looks goofy to me.  Also upon close inspection one of the 30 amp 
ganged circuit breakers is marked (faded and hard to read) 50 amp!

I would have expected #10 wire to the hot water heater. It does appear 
that #12 wire would carry the load OK and the run is short.  But why a 
30 amp breaker?  Possibly to handle a brief high current condition 
when the heating element is cold?  For what it is worth, there is no 
evidence of overheating of the wire insulation either at the breaker 
or water heater.

By the way, there seems to be considerable confusion on how much 
current handling capacity #12 wire has in romex.  I see numbers out 
there from 20 to 27 amps.  Anybody got a definitive source.

The timer I've found mounts in a standard switch box and is the size 
of a ground fault interrupter. I'll be able to expand an existing 
outlet box right next to the breaker panel to accommodate it.  It has 
its own clock (digital) battery backup in addition to non-volitile 
memory for the on/off cycle.  It will drive big relay in the the 
circuit breaker panel.  Will be a nice neat installation.  Won't have 
to climb under the house to bypass or reset as would be the case in a 
standard timer installation.

73 de Brian/K3KO