40 amps in a prewar coop

40A is about 4000 watts -- four microwaves, or a microwave and two hair dryers, running simultaneously. (Air conditioners vary based on the size and efficiency.) Obviously people have lived with that for decades in this unit, and it's not unusual for the era. It is also considered a bit small by modern standards.

Upgrading is likely so expensive and complicated, or constrained by coop restrictions, as to make it impossible for all but the most highly-ambitious and well-funded renovators.

Using the existing feed, you will not be able to add large loads like electric ovens, an electric dryer, a video production studio, and so on. Be sure your lighting is CFL or LED (smart anyway). Air conditioning will stretch things to the max, and you might be constrained in the capacity of replacement AC units, but assuming there is existing AC things should continue working ok.

So basically it's fine if you are a relatively lightweight residential electrical user not looking to add much, but if you have big dreams it might not be enough.

What did you bring the electricians in for? Basic rewiring of the existing stuff?

Thank you.

We would be a family of 2 adults and 2 kids.
So lots of computer use, phone chargers, coffee makers, vacuums, AC's, kitchen devices. Stove is gas, no washer/dryer, no video production studio. I don't know what "lightweight" is considered nowadays.

We brought the electrician in because we discovered that all the kitchen appliances were being run off extension cords. So someone has to rewire all of that. One electrician said that they'd have to knock through plaster walls to get to the fuse box, and he thinks it's full as is. The other said he could go through the roof of the building (top floor) and it's no problem.

There are also very few sockets in the apt, so we'd need additional outlets, and to replace some with 3-prongs.

You're going to be limited as far as how many devices you can use at once. For example, using a hair dryer with a couple of AC units running probably isn't going to work.

A good chart is here: http://www.donrowe.com/usage-chart-a/259.htm

Note that watts = volts x amps. Your electrical service is at 120 volts, so you have 4800 watts.

Can you install another fuse box by bringing a line up from where Con Ed brings it in (like the basement?) Maybe snaking it up a fire stairs?

Don't think you'd want to "go through the roof of the building" as that would probably make you responsible for any leaks in the roof that developed.

Also, can you check with other people in the building as to what they've done re: the electricity. It really does sound as if the 40 amps is way too low.

There are no fire stairs inside the apt, if that's what you mean. Good thought about roof leaks and how that would affect our wiring. I thought that sounded fishy, it's not like it's an attic or a crawl space.

And yes, that's our big question - what are the other tenants doing? I know there are families in the building. There's even a dentist on the first floor. How are they making 40amps work?? Why aren't their kitchen appliances on extension cords?

If 40amps is the norm, how are we supposed to take any pre-war coop? Are they all like that?

@Sheabear - didn't mean fire stairs IN apartment - just if wiring could be brought up and then somehow snaked through the common corridor to your apartment/fuse box.

And roof leaks would not just affect your wiring, they would affect your apartment, and possibly your neighbors' as well. Plus being responsible for repair/replacement of roof is no small matter.

Sheabear - 40 amps is enough for a 2 bedroom 1 bath apartment because you will not be using all of these appliances at the same time. Many appliances, like your coffee maker and microwave are only used for a few minutes. Other appliances don't use their max wattage continuously. So your refrigerator which is listed at 600 watts only draws that when the compressor is running. Otherwise its just a very small fan inside an insulated box and draws a fraction of that energy (probably under 100). The same is true with air conditioners. They only draw the max wattage when the compressor is running.

So on a very hot day, if you have two ACs on (and their compressors are both simultaneously running), were microwaving something and someone was using a blow dryer, your lights would start to flicker, but this just doesn't happen often so its not something to be too concerned about. Now assume that you are using your microwave, someone is blow drying their hair, and only one medium size ac compressor is running (a group of events that would only last a few minutes because, again, microwaves and hair dryers are used for a short period of time), your total wattage use would be around 3700. You could still be running your lights, a tv, and a computer, without any problems.

Re the wiring routes to your kitchen, the electrician will definitely need to cut into the plaster walls and ceilings anyway to add outlets elsewhere, add the necessary wiring in the kitchen, etc. You just have to budget for repairs (preferably some version of full skim-coating and paint, not just patches) as part of the package. Don't let anyone touch the roof.

And if they're doing this much work, replace the fuse box with a new circuit breaker panel, even if they could technically shoehorn everything into the existing box. Worthwhile upgrade and a signal to future buyers that the electrical system has been taken care of.

Thanks for these really great responses. That was my instinct about not touching the roof too.

I know this is probably an impossible question to ask, but with all that work, what's a ballpark average amount one should set aside for a electric job like this? New wiring of appliances, new outlets throughout, new fuse box potentially (if that's even allowed).

I'm asking because I don't know if this is 5k, or 25k, or 100k.

More on the order of $25K, depending of course on a lot of factors.

I just had a 1 bedroom/1 bathroom totally rewired at a cost of 14.5K. That included an upgrade from a fuse box to a circuit breaker, replacement of all outlets with 3 prong receptacles, 10 new outlets, map of all the outlets, and relocation of the ceiling pot lights in the bathroom. I have 30A and the super said that was more than enough for the apartment since the A/Cs are tied into the building's wiring, not the apartment's. He said that the biggest draw was from the kitchen appliances and the new ones are all energy efficient.

The deal did not include the replacement of all the ceiling fixtures or the plastering of the walls. I had a contractor lined up for painting the place, so he handled the wall repairs. Note though, that we skim coated all the walls so that the patches would not show. The painting and plastering came to another 16K due to the pre-existing bad condition of the walls and ceilings.

Great info, thanks!! So interesting!

@jelj13 - How long did the whole project take?