New Restaurant calculations help

Status
Not open for further replies.

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Where does it say in 220.88 that I disregard the large heat load? Could easily be dehumidification heat. 10 kW is a common strip heat number.
220.88(C) says "the largest of the following six selections" meaning you could loose the heat if it is smaller than the AC.

Roger
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
There is no 220.88(C). 220.82(C) says this but that applies to Dwelling Units, which I would say a New Restaurant is not.

BTW, you are correct about it being Dwelling Units, I was replying to Jumpers post.

Roger
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I can't understand why you all think you need to use both the a/c load and the heat load. They won't be on at the same time

220.60 Noncoincident Loads. Where it is unlikely that two or
more noncoincident loads will be in use simultaneously, it shall
be permissible to use only the largest load(s) that will be used
at one time for calculating the total load of a feeder or service.
 

jumper

Senior Member
I can't understand why you all think you need to use both the a/c load and the heat load. They won't be on at the same time

Because of the footnote in the table.

Note: Add all electrical loads, including both heating and cooling loads, to calculate the total connected load. Select the one demand factor that applies from the table, then multiply the total connected load by this single demand factor.

You cannnot double dip on the demand factors here. If it was a standard calc I would do that, but the optional method seems to disallow it.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Because of the footnote in the table.

Note: Add all electrical loads, including both heating and cooling loads, to calculate the total connected load. Select the one demand factor that applies from the table, then multiply the total connected load by this single demand factor.

You cannnot double dip on the demand factors here. If it was a standard calc I would do that, but the optional method seems to disallow it.

You may be correct but it makes no sense to add the heating and cooling unless it is a heat pump that comes on with the heat strips. If that is the case then perhaps mike holt has it incorrect.
 
220.88 New Restaurants.

220.88 New Restaurants.

Guy, when you use a rule, you use it as written, includint tables and notes to table. The note to Table 220.88 is as follows: "Note: Add all electrical loads, including both heating and cooling loads, to calculate the total connected load. Select the one demand factor that applies from the table, then multiply the total connected load by this single demand factor." So when you are using Section 220.88 and apply Table 220.88, we then apply note to Table 220.88. Yes, we do include a/c and heat. It doesn't have to make sense, we just have to follow the specific rule. Section 220.61 is contained in Part III of Article 220, it does not apply to any rule contained in Part IV.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Mike agrees there is an error in the answers. The correct answer should be 441 amps based on 8000 va for lighting-- no 125% should be added to this. Add all the other stuff and you get 105,850 va

105850/240 = 441 amps

There is a note that he wrote that says to see annex D example D3 for continuous loads



The answer for 26 is 656 amps
 

jumper

Senior Member
Mike agrees there is an error in the answers. The correct answer should be 441 amps based on 8000 va for lighting-- no 125% should be added to this. Add all the other stuff and you get 105,850 va

105850/240 = 441 amps

There is a note that he wrote that says to see annex D example D3 for continuous loads



The answer for 26 is 656 amps

Thank you. So just a minor typo. It happens.
 
Status
Not open for further replies.
Top