contractors and landlords please help answer this

[Varinder Kumar]

My tenant wants to purchase a welding unit and  ends a 220 volt outlet for it. The AC unit is plugged into a 220volt outlet but it's not accessible.
1.Is it okay to get a 220 volt out installed? 

2. My tenant said he would pay for it, and WA to to know how much it would be. So how would I go about setting this up legally? 

3. Should I accommodate him in the first place? 
Please advise as I want to take the appropriate steps.  Thanks y'all. 

[Ned Carey]

A good electrician will know the answers off the top of his head. 

My concern would be fire risk if he is welding inside your property. Will your insurance cover that? You certainly couldn't claim you didn't know he was welding if you installed a 220 line to accommodate him.