Exterior outlets
 

On a 1929 house, can I "assume" that exterior outlets (garage, porch) are wired to be adequate for a 10 amp yard machine? If not, what should I look for to check this?

That is an open ended question, and one that you will not likely be able to get a straight forward answer two... There are multiple issues
- Although the house may date to 1929, does the wiring
- what size wire was used, and was it used for the entire run
- what else is on the circuit.
- what is the circuit rated for
- has the electrical panel ever been updated
- is the circuit even grounded
- is the yard machine 10 amp continuous, or 10 Amp peak....

.... I could go on but you get the point...If your in doubt I would suggest having an electrician come and inspect.

The problem is that it is legal in NH for a homeowner to do their own wiring.
So the outlet may be up to par... but the run back may not. Most specifically at the box.

I wouldn't expect a 1929 house to have outside outlets as original, so likely added later. If they are GFCI (lift the cover and see the reset button) you should be OK, as those would be more recent. The assumption is that you have a new panel with circuit breakers, not fuses. Is this something you run with an extension cord, (i.e. only runs when attended) or something unattended like a robot lawn mower that is always "on" and self docks for recharge?

I use "Heat Trak" pads to melt snow and ice on my steps. The outlet is switched on/off inside the house, but the pads also have their own in line GFCI breaker on the connecting cord. The mfg. recommends setting and breaking the breaker before each use. These are low amps <10, but could be run for hours at a time, unattended. I've scheduled an electrician to add more outdoor outlets so I can extend the pads without extension cords. Point is, whatever device you're looking at, it may have some extra safety already added.

Thank you very much for the detailed information. I didn't even realize that this could be an issue.

If the wiring or something else is insufficient, it will trip the circuit breaker, right?

I have a 12-amp leaf blower. I've used it for extended periods on both of the exterior outlets with no problem. So should the 10-amp dethatcher be OK?

If the 12-amp leaf blower worked than the 10-amp dethatcher should.

As for the first part... actually the breaker trips when more current is drawn through it than should be. So an under rated breaker on more than ample circuit would be what you are wishful of.

For instance, if the outlet is 15-amp, and the wire is 14 gauge, but someone connected it to a 20-amp fuse/circuit breaker (or worse put a penny behind the old screw in fuses)... the wire and outlet would overheat long before the fuse/breaker did its job - problem.

But if the outlet is 20-amp, and the wire is 12 gauge, but someone connected it to a 15-amp fuse/breaker, then the fuse/breaker would trip prior to the wire/outlet overheating.

Of the three components, you want the fuse/breaker to be equal to or he lowest rated. That way, it goes first.