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What amperage panel do I need for a hair salon with 14 stations all of them drawing 16 amps each at any given time? (1800 watts / 110v = 16.36 amps ?)

By my logic we will need a minimum 16 * 14 = 224 amps capable electrical panel?

What is really confusing is the fact that the electricians I contact in NYC all seems to say the best I can get is 200 amp single phase or a 3 phase 100 amp connection. The current connection is 100 amp single phase I think.

I realize there are water heaters etc that can utilize all 3 phases and draw lesser current from each phase, but how does it work for hair dryers for example? Do we just assign say 4 stations per phase etc so that we can get so that we can collectively get 300 amps in theory from a 3 phase 100 amp panel? Is this possible?

  • 200A is 240V. That's 400A of 120V so you should be OK. Though you do have to factor in lights and other loads too. – manassehkatz Mar 8 at 15:30
  • Wait. Are your in NYC? Because normally, you can lay your circuits side by side on the two poles, so 7 circuits per pole... But in NYC, most residential power is 3 poles. So same, but with 5 per pole. – Harper Mar 8 at 15:58
  • This is a commercial question, which is technically off-topic. There isn't really a residential analog except for huge homes or those with an industrial shop. – isherwood Mar 8 at 16:30
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    Will your stations all be drawing the full 16 amps simultaneously? Normally the concept of diversity applies to situations like this. Some clients will be on cutting or washing or dyeing, so fewer than half may be using dryers. – Owain Mar 8 at 18:24
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    Turns out all of you are right. In NYC we can either have a 3 wire single phase connection, which in reality is a 2 phase connection(split phase is the technical term) or a proper 4 wire 3 phase connection. The 200A limit is for either of the two 120V live wires so I can draw a total of 400A combined if I use them separately at 120V each. @manassehkatz can you post your comment a an answer so I can close this thread. Harper, great link. Here is a great video explaining split phase. – jinais Mar 9 at 19:17
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200A service is at 240V. That's 400A of 120V so you should be OK. Hair dryers, curling irons, etc. at each station will be on 120V. You should have a separate 20A circuit for each of the 14 stations. That could be with 15A duplex receptacles (allowable for 20A circuits), though 20A duplex receptacles will give you the most flexibility.

If every station is running at the same time (which probably won't happen as often as you might expect) that would be 16A * 14 = 224A, leaving 176A for everything else. "Everything else" includes small loads:

  • lighting - which doesn't take much (relatively speaking) these days thanks to LED technology
  • computer for the front desk
  • TVs to keep the waiting guests entertained

and potentially 2 large loads:

  • HVAC - primarily AC, as heating would (I hope) use natural gas. Air conditioning, particularly for a space generating 90,000 BTU/hr drying people's hair, can be a significant load. If you are in a big building providing HVAC via a central heating system and a chiller then there is no problem. But if you are in a space where you provide your own HVAC then you need to get a real-world estimate of air conditioning capacity and associated electricity usage based on not just the usual parameters (square footage, number of people) but including the hair dryers running a large percentage of the time.
  • Water heating. My guess is you will use a significant amount of hot water at times for washing hair. If your water is heated with natural gas, no problem at all. But if you plan to use an electric water heater (or multiple electric water heaters) then you need to factor that in as well.

HVAC & electric water heaters are 240V loads. A typical residential water heater might have 9,000W (2 x 4,500W) elements and use a 40A circuit. Your requirements may be significantly higher as you have to allow for 14 shampoos within 30 minutes of the shop opening each morning.

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    Residental HWHs only draw 4.5kW as the elements are not run at the same time – ThreePhaseEel Mar 10 at 1:22
  • @ThreePhaseEel I just looked up one (Rheem, selected largely at random from Home Depot web site) and it looks likely typically they are installed for non-simultaneous element operation (as you noted) but at least some can be installed for simultaneous operation. I'm not sure what the advantage is of having 2 identical elements but not using them at the same time, but apparently that is a real thing. – manassehkatz Mar 10 at 1:31
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The usual way for an electrician or engineer to size a service is to do a load calculation that takes into account everything on the service - not just the receptacles at the stations but also the microwave in the break room, the water heater, the lights, etc. The load calculation takes into account which loads are likely to be on for long periods continuously and "diversity." In this context diversity means taking into account that you won't turn everything on at once.

I am a little surprised at what the electricians are telling you but if they're saying the same thing they're probably right. The size service available to you could depend on a lot of things - the size of the conduit that feeds your space, power company rules, utility transformers, local NYC electrical regulations, etc.

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    You are right. The Con Edison utility company has a 200A limit on individual commercial users. So I guess it is a regulation thing. I did apply the diversity rule, and it turns out, during peak hours all the stations will be running the blow dryers at the same time. There are other factors affecting the load calculation but compared to this those ae minimal. – jinais Mar 9 at 19:23

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