Extension Cords

I just moved some cords around last night for my flower room, and it got me wondering about how much wattage is too much to draw from a single extension cord. I have my 315w, 400w, and ~150-175w mars led panel all hooked up to a three way split onto the end of a single extension cord. Is that too much wattage to draw from a single extension cord?

I have a timer that only has the standard two-pin plug, which means that I would need a three-prong adapter to attach it anywhere to my extension cord for the lights. Is that even safe to do with that much wattage, or should I invest into a different timer with a grounded plug?

It's not so much the "watts" it is the amps!

As long as your not drawing over the circuit's amp limit. Or the line's wire rating. You should be good.

Tips:

Always use an extension cord of the same gauge as the appliance power cord.
Always use 20 amp wire to wire any grow outlets you add to your box or in building a new grow area.
The more you draw, the hotter a line can get,,,see the first tip...

https://www.thespruce.com/select-proper-electrical-extension-cord-1824710

Can't recall the poster's name here. Just his story. This year. Fire! If in doubt go larger gauge every time .

1800 watts max on 10 gauge wire extension cord. (15 amps @120 volts)