What happens if two 120 volt loads are connected in series to a 240 volts service?

Burn correctly if they were ordinary light bulbs having the same power rating.

<><><>

However, if the loads were different, such as a 100 watt lamp and a 40 watt lamp - neither of them would produce the same amount of light.

If the loads were of very different types - say a 120 volt motor, which is a magnetic device, and a 120 volt computer, which is an electronic device - you can't say for sure how well they would each work when connected together in series across a 240 volt service without knowing a lot more facts about them.

What happens will always depend on the individual resistances and impedances of each load and how different they are.

<><><>

As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.

Before you do any work yourself,

on electrical circuits, equipment or appliances,

always use a test meter to ensure the circuit is, in fact, de-energized.

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB

SAFELY AND COMPETENTLY

REFER THIS WORK TO QUALIFIED PROFESSIONALS.