How do Canadain rv standards differ from U.S.

I am not an expert on this by any means, but we have Canadian friends that imported an RV into Canada. The issues they had related to outside lighting and the drivers seat). There may have been other issues. There is a list of RV's that can be imported into Canada as is. Many can not be. My understanding is that these are safety issues and are not trivial.

Contrary to the above comment, the standard differences are not BS, there are variations because the Canadian standards are more rigorous. Most of the difference relate to high voltage applications where the high voltage standard is 575V in Canada for industry, in the US it's 220/440V.

Having said that, with NAFTA most electrical components are now certified to CSA/ULC standards as it's a hassle to make and market stuff separately. Can't speak to importing and the requirements but I would check if you plan to import an older unit. I had an older Prowler RV, it had substantially different electrical schematics for CSA and non-CSA units. The Canadian version had about twice the number of circuit breakers in the panel compared to US units.

It's all about how to separate You from a few Bucks! Commonly referred to as BS.
We have Imported Several RV's from the States into BC Canada over the Years!
There is Nothing different about My current Motorhome than One the that was originally Sold here in Canada! The only difference was the Price !
There are restrictions placed on what You can and can not Import,but these restrictions have absolutely nothing to do with CSA or any other label affixed to the side of the Vehicle! They have to do with the ability of the Vehicle to provide proper safety to the occupants. eg. Seat Belts and Child restraints in the event of an accident.
Don't worry because the few that are not allowed to be imported are such a small percentage that You likely won't be even considering buying one!

Equipment in Canadian RVs must be CSA approved, and have the CSA label attached to the RV.

Propane must meet Canadian Gas Association standards.
There's a good brochure here, from Manitoba http://www.firecomm.gov.mb.ca/docs/rv_brochure.pdf

CSA standards differ from US standards. An example would be the Honda EU2000 generator. There was a recall in the US but not in Canada. The American-sold generator did not meet CSA standards so the generator was modified for sale in Canada.
http://www.consumerreports.org/cro/news/2012/11/american-honda-recalls-portable-generators-due-to-fire-and-burn-hazard/index.htm