dryer plug to two 120VAC 30A ?

[RBM]

Sorry, but you clearly don't have a clue

[Doug Miller]

No, he doesn't. Think about it a little bit.

Hint: 2 * 110 * 15 is not the same as 220 * 30.

[Doug Miller]

Bad enough you posted an egregiously incorrect response -- didja have to post it three times??

[Mark Lloyd]

There's NO 60A line there. You have 2 30A lines which cannot be connected together (this would produce a short circuit, actually making 0A available). To get 120V you use ONE how wire and neutral. It would be possible to connect two 30A appliances, but not a 60A one.

I have seen where someone was using a 240V receptacle for holiday lights.

It was an older house, so probably 3-wire. That was supposedly unsafe (current through a bare wire?) but probably not VERY unsafe.

[Mark Lloyd]

2 at 110/30 or 4 at 110/15.

[Dave Martindale]

It will function fine in normal use. But the wiring and the outlets in your 120 V strips are likely designed to carry 15 A, while they are "protected" by a breaker that will carry 40 A. This isn't safe in an overload, unless you change the breaker to a two-pole 15 A one.

Dave

[Mike Hartigan]

The breakers are designed to protect the wiring in the house, not the devices plugged into it. From that perspective, there would be no overload hazard created by this scheme.