wrote:

In another thread, I was asking about heating a crawlspace in my
cottage. Here is a different, follow-up question.

The previous owner (who lived there year round) had a heater in the
crawlspace. The heater doesn't work (and had not thermostat etc
anyway), but the plug he used was usual to me. I must confess that I
am clueless about this stuff, but it looks like this
http://doityourself.com/store/4170171.htm . The place is wire at 120 V
only, and the recepticle is for thinner prongs than the big 220 plugs.
Can anyone tell me what this outlet is? And is it materially different
than a regular outlet (i.e., if I was going to put a heater, is that a
better outlet that a "normal" outlet)? Finally, does anyone know where
I would buy a heater which would fit such an outlet.

That's just a 15A/220V outlet. The design is intended to prevent using
a 110V appliance or a 220V appliance needing more than 15A service.

As for finding something using that plug style, it would need to be a
220V/15A rated device.

Would be good to know what the service breaker for the circuit is and
what the wiring is before going too far. If it is really a 15A service,
you'll not want to get something larger than that and change its plug to
match, for example.