I've used a metal cutting circular blade on my chop saw to cut 3/8 ss bar and it worked very well. You could try that. Lots of sparks and smell though.

I would not use a wood circular saw to cut metal, even if you put a metal blade in it. This is because the safety housing and blade guard on a wood circular saw is not designed to contain chips etc from metal cutting. It could ruin the saw as well as endanger you.

There are some circular saws specifically designed to cut metal; they run around $400.

The jig saw fitted with a metal blade might work, but it could be slow going. But if it's not a long cut and you don't care how the cut looks (if it will be covered by outlet cover or other trim) then it might do. You'll probably need to drill a hole and then cut out from there for the outlet opening.

I've seen small angle grinders at Harbor Freight for as little as $16.

A problem could be the wood backing... an angle grinder might not like all that cellulose. But I suppose if the metal were to be removed by the grinder, one could follow up with a jigsaw.

You can use the jig saw. I would use the finest tooth blade since the material is thin. The wood backing is good for supporting the metal but the fine blade makes it longer to cut it. You also want to use a slower speed when cutting. My 2 cents.

AIrcraft snips will probably go through it pretty easily. They run anywhere from $10-30 each (right cut, left cut, straight cut).

My 2 cents worth....Needed a chopper for my apple cider press that I put together....whole apples do not press good...I used a non coated RV kitchen sink welded 2 bottom angled pieces to make a chute... cut them and the 1 inch by 4 inch blades with levered snips [aircraft style?] except for the parts right by the top counter part I used a blade in the circular saw as I was out of cut off wheels for the die grinder.. It grabs to beat heck and disorts the metal I wasnt looking for beauty just a way to chop up apples to pressable pieces so I would drill, then use right, left straight and fingerslicing snips...dont squint and stick your tounge in your cheek, dont help just catches your poor finger...

17 gage stainless steel is about 56 thousands of an inch thick. That's a little less than 1/16 inch in thickness (.0625"). I wouldn't want to tackle that gage with aircraft snips, especially if it has a wood backing, and stainless steel is kind of tough to begin with. But you could try. Another problem with snips is that they leave sharp edges and can also dent/warp the metal.

My first choice for cutting this to size would be a hydraulic shear. Then I'd do the cutout with an abrasive edge bladed jigsaw - assuming the edges will be covered by trim. A nibbler of sufficient capacity might handle the cutout, too.

OK my penny's worth [bad advise loses value] After reading spambedamn's reply....yeah snips and a sixteenths of an inch of stainless [painless?] would not be too much fun or practical..the sink was a little hard to do but not bad .. something like this I'd drill holes for sticking a fine toothed sawzall into and go slow candle wax makes a pretty good lubricant that wont mar the finish like some oils may

If I were cutting stainless steel I would use a 4 inch angle grinder with a (steel cutting disc )as apposed to a grinding disc, which is thicker, and used only for grinding edges or grinding down lumps or bumps on steel surfaces, or dressing off weld joints etc. You mention that you are fitting sockets within your stainless steel panel, what I would do in this case is to measure (scribe) the length by the breadth of the sockets on to the panel surface using a (black felt tip pen) and reducing by 1/8 of an inch at the four corners on the inner side and there by giving you a clean professional finish to the fitted socket when it is fitted .Now you are asking yourself how do I get nice clean cut corners? ItÂs very simple really, you use a drill with a 1/8 steel drill bit, some plasticine or putty and you create a little well at the 4 corners and fill the well with oil, engine/cooking /gear oil, you can even use water if you donÂt have the above , the reason for executing the above process is because the drill bit will heat up and melt ,the stainless steel being harder than the normal mild steel bit that we normally use. I hope my little titbit will be of some use to you in your project.
Always wear eye /face protection when using the above,.

If the wood backing is less than 1/4" a Metabo grinder with a cutoff wheel will cut thru it like a hot knife thru butter. Most tool centers will have the metabos, cost about 200 bucks go ahead and get the 6in and a few blades you will find many uses for it, if you do much metal work.

If you don't feel it's worth the effort then I'd go to a local fabricator/bodyshop and have them plasma cut the piece you for you. I'm lucky enough to have a friend down the road with one and it took 1/2 an hour to layout and make all the cuts on the 72" backsplash I installed for the kitchen.

Here is a pic for reference.

Here is a link that might be useful: Backsplash