An arc-fault breaker should have prevented this.
A better practice for installing receptacles is to "pig-tail" the wires rather than "daisy-chain". By tying the two or three hot (ungrounded) wires together and taking a pig tail to the receptacle and doing the same thing with the nuetrals (grounded), you allow the load to bypass the receptacles between the load and panel.
For example-- if the dehumidifier is plugged into the last outlet on the circuit (furthest from the panel).
With the wires daisy-chained, the load travels thru each receptacle.
With the wires pig-tailed, the load travels thru the wires, bypassing the receptacles.
I hope I don't confuse anyone too much with this