Are you thinking single phase just to save some money?
At least with 3 phase, if anything, however unlikely in the future requires 3 phase, maybe a big printer, copier or who knows what, you have it covered. What's the load on the original panel?

 

Yes you can use a single phase load out of a 3 phase panel. Done all the time. You need to check how much load there is on the main panel and see if adding extra single phase load will overload one or two of the phases. Also the main panel will have a maximum stab rating so you may not be allowed to install a 100 amp breaker.

Main disconnect would be required if your in Ontario depending on if the new panel is for a separate unit within the building or not. See 14-418 in OESC

As for the load calc using table 14 is good but you should also look at the actual load as well and consider any possible upgrades.

 

I dont think you will be doing any one a favor by installing a single phase panel on a WYE system.
Will you save maybe $200?

 

I just thought of a great idea, if my calculations were correct and 45A is all it needs, instead of doing all that work for a subpanel, please see attached pictures.
On the first picture we have the main panel and a little subpanel they installed for a few plugs, since I only need maybe total of 7 breakers. If I run EMT to the new locations from that panel should be OK right???

The second picture is the drawing they gave me with a colour legend I made.

If you guys can confirm of this works, then this will save my client a lot of money, I don't want to lose the job because I over did it for what they needed. Also those 3pole breakers from the old main panel are sooooo expensive.

Please let me know ASAP if you are confident on your answer. I do more residential, it's been some time since my last commercial job I want to make sure I'm on the ball on it.

 

I just thought of a great idea, if my calculations were correct and 45A is all it needs, instead of doing all that work for a subpanel, please see attached pictures.
On the first picture we have the main panel and a little subpanel they installed for a few plugs, since I only need maybe total of 7 breakers. If I run EMT to the new locations from that panel should be OK right???
.

First off, what is the load on the little panel and does it have room for what you want to add. Not room for breakers, room for more load and still be below 80% of it's main.

Second, that main panel looks like an FPE bolt-on to me?

 

Here are the pics

 

I would hate you if you installed a very small single phase panel in my facility.
Think of the next guy and how screwed they will be standing there looking at a 60 amp single phase home depot special some dufus installed to save a buck.

 

I get you, I am just looking at the options
, the sub panel existing there is a 3phase 60A panel, should be good right??

 

I read the previous answers and THANK YOU for the quick responses, just want to answer some of the questions,
I didn't put the amp rope to check each phase, just saw that is a 225A, will have to do that.
I just been checking with my supplier for the cost and from a single phase and it's a big difference, the main old commander breaker they said is hard to find, a 100 single phase would be $250 but a 3phase they said it may be on the 350-450.
The panel is $625 compared to a $150 single, teck wire also one less conductor.
Think when I add it all up it may be close to $800 cheaper.
But if my last post is correct then it would all work out good haha.

 

The panel is $625 compared to a $150 single

You're comparing a commercial grade 3 phase panel with a residential single phase panel. You won't be doing anyone any favours by installing a resi panel in a commercial building. That little sub that's already there is a resi panel. Whoever did that is a clown. You should only be looking at putting commercial grade equipment in a commercial building.

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Definitely a FPE bolt-on. I can't remember off the top of my head, but don't the larger FPE 3 phase breakers take both sides of the bus, or was that just the Stab-Lok?

 

Stab lock 60 amp and larger

 

The reason you have commercial grade, industrial grade, and residential grade is because they all have different levels of abuse and use.

You might sell jobs at a lower cost installing lesser grade materials, but you'll do two things:

1) Build a reputation for installing materials that suck.
2) Lose your buns on warranty work.

Sometimes the question of if it is legal or not is irrelevant, is it wise or not is a better question.

 

3. Chicks dig the commercial and industrial equipment.

 

This sounds more and more like a side job and not being done by an electrical contractor.

 

Your assumptions are Wrong, I am an electrical contractor, I havent been doing commercial for some time so I wanted to check on somethings.

I find in every threat on this site there gotta always be someone saying that to the OP, it gets old real fast, like you never need a refresher or a double check on anything.

 

Sorry for sidetracking the conversation regarding quality, but my first question is whether the floor panel includes the A/C loads for the floor? If so, the 50W / sq m estimated loading is way short. Do you need to pick up any A/C or heating loads in the new office space

Assuming only one 200A, 3 phase panel per floor and 8 - 10,000 sq ft of existing office floor space, that panel is probably full already (at least according to the CEC)

Even without any A/C, I would ROUGHLY estimate that the CEC non-continuous load for the existing office space is already at around 130A. This doesn't leave much room left over for the new office. Based on very limited information, I likely wouldn't feel comfortable adding anything to that panel. I would normally recommend going back to the upstream distribution.

Lastly, I was a little concerned about your circuit count. I usually don't load up the office receptacle circuits with 12 plugs. I usually feed no more than 2 small offices per circuit. Two computer stations plus some nearby lighting usually fill a circuit.

CAVEAT: Information presented in this post does not constitute professional engineering advice.

 

Thanks for your input, it is not going to supply any A/C or heating, I may just get an ESA inspector to come by for an hour consultation after I get the job to tackle all this questions, may be the best way to be safe.