> it can draw up to 20A

can being the operative word - the LRA (Locked Rotor Amps) of a typical fridge/freezer's compressor might be that high, but starting current is not unless something is hideously wrong. I've never metered mine, but I have ran three fridges and a deep freezer off of a 2200/1800 (start/run) watt generator with zero issues, and plenty of headroom left. The generator has tiny dip when the compressor kicks on, and then it jumps back.

You are correct that sizing cords is very important, though, and something that most people don't do. Also if you have a roll-up extension cord (the kind with multiple outlets at the end), it's vital that it is completely unrolled when in use, so the cord doesn't heat itself.

I run 12 gauge splitters --> 14 gauge for individual loads, but I also know exactly how much those loads are pulling, and have verified it's within safe limits for the wiring.

It's worth remembering that a house's wiring is almost always 12 gauge, and is rated for 20 amps assuming the correct outlet.

I thought most recent US houses were built with 14 gauge wire which is only rated for 15 A? It's cheaper than 12 gauge and code-compliant (at least in my state).

I used 12 gauge in my house on purpose but sadly I don't think that's the norm.

That very well may be true - I've never had a house newer than about 20 years old, and they've had 12 gauge everywhere.

Most recent houses I've seen are using 12 gauge for outlets and 14 gauge for lighting. 12 gauge is mandatory in many locations, since 20 amp circuits are the minimum by code. Either way, 12 gauge is always safe obviously.

That's exactly what I did; lighting got less power hungry as we moved away from incandescent so there was no reason to continue to use fatter copper there. But it would have been legal to use 14 gauge/15A for every circuit in my house in New Mexico; I chose to use 12 gauge/20A for outlets instead.

Not actually true, to be clear, for outlets. Yes, the majority are allowed to be 15 amp circuits, however there are a few circuits (notably, ones in the kitchen) that by code (any recent code, NEC 2007 or beyond I think) that mandate that they be 20 amp circuits.

Notably:

* Kitchens must have at least two separate 20 amp circuits (for use for small appliances on countertops, traditionally) for general use

* Fridges need a dedicated 20 amp circuit

* Microwaves need a dedicated 20 amp circuit

Beyond that, yeah, absolute minimum is 15 amp throughout the house.

I built my first house in 1997 so my memory of NEC is mostly from then. It seemed ludicrous to run 15A circuits especially to kitchens and bathrooms, so I didn't. It did require GFCIs in the usual places back then. I built another house in 2007 and by that time AFCIs were required in bedrooms.

The code does seem to get a bit better over time.

Honestly, the fact that every consumer hardware store sells racks upon racks of 50+ ft 16-gauge extension cord is obscene. I upgraded my 60 ft lawnmower cable to 12-gauge for safety reasons and was shocked to discover my lawnmower wasn't just safer but also visibly more powerful, which I didn't think was possible.

Folks, spring for one or two good 50+ ft extension cords. You don't need a lot of them and the cheap ones are bad for your equipment and your safety.

  > wasn't just safer but also visibly more powerful

All that energy that used to go into heating up the extension cord, are now getting to your tool.

I personally argued with the guy who installed my EV charging station, because I wanted thicker wire and was willing to pay for it. I don't want wires heating up, I don't care if it's code compliant it is energy wasted that could go into my EV. And the thicker wire is not much more expensive nor difficult to work with.

>Honestly, the fact that every consumer hardware store sells racks upon racks of 50+ ft 16-gauge extension cord is obscene.

I can't help but face-palm at this sort of hand wringing. It might not be "right" but it works.

If the 16ga cords regularly melted people wouldn't buy them in those lengths, they wouldn't fly off the shelves, they'd get stocked in lower volume and you'd see less of them on the shelves.

The fact that they don't melt themselves even when used with fairly substantial appliances (large-ish homeowner sized table saws and compressors, all manner of portable power tools) is a testament to how conservative the official recommendations are.

>and was shocked to discover my lawnmower wasn't just safer but also visibly more powerful, which I didn't think was possible.

Voltage drop

For lots of things it's fine, yes, but for tools I would not try it. My brother (a contractor) had two compressors die from undersized extension cords before learning about properly sizing them. More resistance --> lower voltage --> motor spins slower --> pulls more current --> compressor electronics die.

I'll grant you a contractor's usage of any tool is much higher than a typical homeowner's, there's still no reason not to get the beefier cord. Buy once, cry once.

I just mean it's really silly you can go to a Canadian Tire and there'll be a 10-amp 82 foot extension cords for sale right next to the 12 amp corded lawnmowers, and if you want to satisfy the spec you'll have to search all over the store for contractor-grade hardware.

Good introductory video on the subject:

https://www.youtube.com/watch?v=K_q-xnYRugQ

True. I was exaggerating a little. I'd never use a $20 16 gauge Harbor Freight extension cord for anything important, especially if it's over 2 meters long.

It was a great point, though. And, my pedantry aside, having your car - which bring all the benefits of an EV - be a decent electrical backup system and replace a standalone inverter generator (at least $1k, and you'd have to buy appropriate extension cords, anyway) or a whole-home standby (at least $15k) is an exciting prospect and great solution for a really large number of US households.