Pre war apartment's electrical wiring

Converting to a truely grounded system (the 3rd prong is grounding) isn't necessary. It should have already been properly grounded. Instead, just get an adapter and make sure that you screw the grounding into the outlet cover properly. The screw that screws into the outlet face is the grounding.

The only thing I worry about with an old electrical system in a prewar is that most wiring is limited to 15amps - lighter gauge wiring used. You might not be able to run a vacuum cleaner without blowing the fuses!

Look for a circuit breaker - if there is one installed, then the wiring may have already been upgraded.

Went through the 110 versus 220 volatage debate on a renovation in my pre-war 3 bedroom apartment.

Given that we don't have central air and instead have individual units in each room, my contractor said we were on the cusp of exceeding electrical capacity. Contractor felt that if all AC's were running we probably could not run the dish washer or a vacum cleaner.

Since I was doing a gut renovation I decided to upgrade the electrics as well. This entailed running a new electrical riser (about a three inch pipe) from the Con Edison meter in the basement up into my apartment. Since I am only on the third floor it made things a bit easier.

This is a pretty standard procedure for the renovation of pre war apartments but it is not an easy job if there are challenges running the riser up. Usually done in the stair wells but can be done in an elevator shaft or any other vertical space.

As part of my overal renovation contract I was charged $5,000 for the electrical upgrade. Imagine the floor is important because running a riser up 18 floors as opposed 3 is a lot more labor intensive.

Before getting too hung up on the debate take an inventory of your appliance usage, it may be sufficient to operate with 110 volts. As a rule of thumb if someone is touting a big pre-war apartment that has been renovated they should have upgraded the electrics to 220 volts.