As per the MTO,
"Light trailers that transmit to the highway a total weight of 2,800 kilograms (6,173 lb)
or less are not included in determining registered gross weight."
http://www.mto.gov.on.ca/english/trucks/commercial-vehicle-faq.shtml#a3
This is for commercial use. Furthermore, the handbook says:
http://www.mto.gov.on.ca/english/dan...ion5.4.1.shtml
"You must have a valid driver’s licence (Class G1, G2 or G) or higher class of licence to tow a trailer with a gross vehicle weight of up to 4,600 kilograms. If your trailer and load exceeds the size and weight specified in the Highway Traffic Act, you may need a higher class of licence or an oversize vehicle permit to tow it. Oversize permits are available at some ServiceOntario centres.
It is against the law to tow more than one trailer behind non-commercial vehicles."
The reference is in regards to a trailer up to 4,600 KG in weight and does not include the tow vehicle.