Demand Factor=1

[INGMRS]

Hello Sirs,

I have a doubt, What happen when the demand load is equal to the connected load?. i mean, after to apply the demand factors for lighting, receptacules, kitchen equipmet, etc, you got a demanda factor of 1 for the feeder?

How to proceed?, i mean, is not logical that every load connected is going to be working at same time.

Please see the attached file with my calculation.


Thanks for your comments,

 

[charlie b]

First of all, there are many women who actively participate in the forum. I suggest not using the greeting “Hello sirs.”

Secondly, I cannot pass judgement on your use of demand factors, since the spreadsheet shows its loads in a language I do not understand.

Third, you have an error in cells E19 and E20. You arec alculating the connected load by adding up the cells above E19, and those cells include the demand factor of 1.25 for lighting. You then make cell E20 equal to cell E19. By doing so, you force the spreadsheet to show equal values for connected load and demand load. What you need is another column that takes, for example, cell C13 times cell D13, and does the same for rows 14 through 18. You then add that column and put the total in cell E19. Then, instead of making cell E20 equal to cell E19, you make cell E20 equal to the sum of cells E13 through E18. Then you can see a different value for connected load and demand load.

 

[Adamjamma]

ok, as I am also a student trying to learn, I notice several things here. It is a church. So, lighting demand... Constant for the last lighting load as that would be the signage outside..
Ventilation..ie fans.. not under lighting normally. Would not usually be considered constant in a church, unless the church is used all week as well.
Cooking... unless this is running a daily soup kitchen would probably be minor. so not part of major load.
Altar circuit.. Assuming this is for sound system etc, but still, usually not considered a constant load but occasional load.
In fact, with the exceptions of the Pastor and the Secretary offices, most of the rest of the circuits are usually considered occasional circuits and the load is usually for vacuum cleaners.

Lavatory Circuits.. Both bathrooms may be on same circuit unless you have those fancy hand dryers in them... those require dedicated circuits according to the manufacturers, for no more than two of them per circuit, or at least the ones I am used to are rated that way.

Your local authority will probably change the kitchen circuits from one to three... refrigerator, and two for outlets.. plus a stove if you have one, or a microwave circuit if you have one of those.
Most of the churches I have dealt with, the local authority used the residence requirements for the kitchens... but check on that.
only gear here that counts for full load is stove and fridge... you listed the microwave but not in the kitchen...
again, the separation of circuits... cocina and microondas are both kitchen only... you list classrooms... so, would need more information on number of classrooms etc...

but, it is a decent start. Just, people on here will have trouble helping because they need more information... That is before you correct the load errors in your calculations.

Note that i need to check on... If you have classrooms, because they use the lights for more than three hours, the lighting load becomes constant, i think... But I may be wrong on that.. time to go double check my code books.

 

[jumper]

ok, as I am also a student trying to learn, I notice several things here. It is a church. So, lighting demand... Constant for the last lighting load as that would be the signage outside..


Note that i need to check on... If you have classrooms, because they use the lights for more than three hours, the lighting load becomes constant, i think... But I may be wrong on that.. time to go double check my code books.

The term you seek is continuous, not constant.

Per NEC definition:
Continuous Load. A load where the maximum current is expected to continue for 3 hours or more.

Note the word maximum. Important.

As a general rule, continuous loads are calculated at 125% of the actual load.

 

[Adamjamma]

The term you seek is continuous, not constant.

Per NEC definition:
Continuous Load. A load where the maximum current is expected to continue for 3 hours or more.

Note the word maximum. Important.

As a general rule, continuous loads are calculated at 125% of the actual load.

Well, how is that counted though, over the week or per day? Because if you take a baptist church, some of them seem to go on for hours... but yet a catholic church is around 70 minutes...if that...
a baptist church uses the main part for sunday service and a few bible studies... perhaps three days out of a week for around three hours each time...

but a school now.. 7 hours a day use of the lights.. so that then becomes continuous... making most of the loads then continuous loads, under these calculations, as you use the lights even in the day.

 

[jumper]

Well, how is that counted though, over the week or per day? Because if you take a baptist church, some of them seem to go on for hours... but yet a catholic church is around 70 minutes...if that...
a baptist church uses the main part for sunday service and a few bible studies... perhaps three days out of a week for around three hours each time...

but a school now.. 7 hours a day use of the lights.. so that then becomes continuous... making most of the loads then continuous loads, under these calculations, as you use the lights even in the day.

Go back and read the exact definition. The time period.

 

[Adamjamma]

Go back and read the exact definition. The time period.

I am considering the time period: MOre info is needed. Type of church, classrooms and their normal usage, are they for daily students, like the church I was with in Dekalb, or only Sunday School, like the one I was with in Conyers. Is there more than one service per day? Is the place used for gatherings on a regular basis?

Under maximum demad and diversity laws used for calculations, these are all factors that change the calculations, as the lighting loads can be changed for various parts of the building from Continuous to Occasional.

The Local AHJ will have their say as well in those loads.
Secretary and Pastors office are normally considered to be Continuous. Outlets and lights.
Kitchen is usually under same rules as residence but, it depends upon the use of the kitchen... if they prepare foods for students it becomes commercial, same as use for soup kitchen more than once per month. This changes ratings of equipment, and types of circuits, as well. Again, falls under the normal use clauses. But normal use of most kitchens in most churches is to sometimes warm up some pot luck, for the preachers lunches, and for warming bottles for the congregation, along with the secretaries popcorn..lol
Most of the outlets within the church and the school are not normally high usage. But, they still fall under commercial usage rules, so they have a maximum number per circuit.
However, if I recall right, for calculations you take the first one at full value and derate the rest...or is that just UK?

Anyway, I am just trying to learn as well... and do not yet have the money to buy the latest NEC codes.. my 2011 copy is in Jamaica.. and so, I cannot verify everything on load calculations. But, I can see the calculations are off and the first place to start is to define the circuits better.

 

[jumper]

Adam, I can only answer and address a direct question using NEC methods.

Any load that draws full power continuously for 3 hours is the definition.

Certain loads will commonly default to continuous such as commercial lighting or certain loads that the NEC says shall be considered continuous such many HVAC loads.

We factor this into our calculations.

 

[Adamjamma]

OK. So most of the lighting here would be rated continuous as churches are considered commercial. Simple and easy to use default setting.

The venting as well, probably, and the fridge circuit.

Only need to no more about the rest of the uses in this circumstance to figure out the rest of the calculations. I do not know what else is considered as default in Commercial codes as I never had to look up commercial codes in the USA, only what the fill tables were for different conduit... in commercial areas... and that as with my boss double checking everything before I touched the first wire..lol

 

[jumper]

OK. So most of the lighting here would be rated continuous as churches are considered commercial. Simple and easy to use default setting.

The venting as well, probably, and the fridge circuit.

Only need to no more about the rest of the uses in this circumstance to figure out the rest of the calculations. I do not know what else is considered as default in Commercial codes as I never had to look up commercial codes in the USA, only what the fill tables were for different conduit... in commercial areas... and that as with my boss double checking everything before I touched the first wire..lol

Not sure what venting means.

A fridge cycles, not a continuous load.

 

[kwired]

Lighting in a church is the easy part.

HVAC - better plan it to be continuous load regardless of what NEC calls it - it may draw little or nothing for most the week, but Sunday it gets pushed hard quite often. Many churches do have somewhat undersized AC units, but turn them on several hours before service starts with the hope it remains comfortable enough until typical time service ends.

Social events at the church, seems to be more common today to see either catering or potluck meals. Catering may be best case scenario when it comes to figuring loading - food often kept warm offsite and if needed small self contained gas burning appliances to keep warmed at serving line. Potluck - often results in many crock pots, roasters, etc. getting plugged in to keep food warm. None of which are continuous load per NEC, but are still significant load. And though they may only be there for a few hours at a time, are a high demand at the time they are there and you must be able to supply that demand.

 

[Adamjamma]

Yeah... if there were set rules on churches it might help but I have seen the buildings sold from one congregation to another... and first built the building for what they did... second did loads of pot lucks until breakers started tripping etc..then got upset because it was a kitchen..lol...
but just like at home.. too much at one time and it blows..

 

[kwired]

Yeah... if there were set rules on churches it might help but I have seen the buildings sold from one congregation to another... and first built the building for what they did... second did loads of pot lucks until breakers started tripping etc..then got upset because it was a kitchen..lol...
but just like at home.. too much at one time and it blows..

If you around this kind of place much, it don't take long to learn that for any kind of reception hall serving line area you never put more than one receptacle (can be a duplex) on a circuit and you must put several of them in the serving line area.

Food prep area you can get away with more than one receptacle per circuit much easier.

 

[Adamjamma]

If you around this kind of place much, it don't take long to learn that for any kind of reception hall serving line area you never put more than one receptacle (can be a duplex) on a circuit and you must put several of them in the serving line area.

Food prep area you can get away with more than one receptacle per circuit much easier.

If I ever get asked to help set up or maintain churches again will remember that.
jamaican churches are easy.. two outlets on each wall... outlets in reverends office...
concrete area to let them set up jerk and soup charcoal pans outside somewhere and put a laundry sink in there for washing up...
no warming trays or such there..or they use those candle things for them..

 

[INGMRS]

Clarifying my calculation.

Clarifying my calculation.

First of all, thanks for your help.


My answers, below next to yours responses.

Thanks!

First of all, there are many women who actively participate in the forum. I suggest not using the greeting “Hello sirs.” R/ ok.

Secondly, I cannot pass judgement on your use of demand factors, since the spreadsheet shows its loads in a language I do not understand. R/ ok

Third, you have an error in cells E19 and E20. You arec alculating the connected load by adding up the cells above E19, and those cells include the demand factor of 1.25 for lighting. You then make cell E20 equal to cell E19. By doing so, you force the spreadsheet to show equal values for connected load and demand load. R/ According to the table 220.12, there is not demand factor for lighting for churches, so it should be 100% therefor connected load=demand load (for lighting), I placed at 125% considering a continuos load, more than 3 hours operating.

What you need is another column that takes, for example, cell C13 times cell D13, and does the same for rows 14 through 18. You then add that column and put the total in cell E19. Then, instead of making cell E20 equal to cell E19, you make cell E20 equal to the sum of cells E13 through E18. Then you can see a different value for connected load and demand load.

 

[INGMRS]

Adding Information

Adding Information

Hello,

Thanks for your reply,

My answers, below next to yours responses.

ok, as I am also a student trying to learn, I notice several things here. It is a church. So, lighting demand... Constant for the last lighting load as that would be the signage outside..

Ventilation..ie fans.. not under lighting normally. Would not usually be considered constant in a church, unless the church is used all week as well.

R/ In this case, the fans are going to be woking more than 3 hours, that is the reason that i consider them a continuos load, 125%.

Cooking... unless this is running a daily soup kitchen would probably be minor. so not part of major load.

R/ Applying the demand factor for electric ranges (NEC TABLE 220.55) it would be at 100% 8000VA.

Altar circuit.. Assuming this is for sound system etc, but still, usually not considered a constant load but occasional load.

In fact, with the exceptions of the Pastor and the Secretary offices, most of the rest of the circuits are usually considered occasional circuits and the load is usually for vacuum cleaners.

Lavatory Circuits.. Both bathrooms may be on same circuit unless you have those fancy hand dryers in them... those require dedicated circuits according to the manufacturers, for no more than two of them per circuit, or at least the ones I am used to are rated that way.

Your local authority will probably change the kitchen circuits from one to three... refrigerator, and two for outlets.. plus a stove if you have one, or a microwave circuit if you have one of those.

R/ yes I have one, sorry the language (Circuito de toma dedicado para Microondas= dedicated circuit for Microwave)

Most of the churches I have dealt with, the local authority used the residence requirements for the kitchens... but check on that.
only gear here that counts for full load is stove and fridge... you listed the microwave but not in the kitchen...
again, the separation of circuits... cocina and microondas are both kitchen only... you list classrooms... so, would need more information on number of classrooms etc...

R/ There are about 8 classrooms, and there are a mimimum of 3 outlets per room, so when you add all the outlets the result of the operation is less to 10000VA, then, all this would be at 100% (nec table 220.44), again connected load= demand load.

but, it is a decent start. Just, people on here will have trouble helping because they need more information... That is before you correct the load errors in your calculations.

Note that i need to check on... If you have classrooms, because they use the lights for more than three hours, the lighting load becomes constant, i think... But I may be wrong on that.. time to go double check my code books.

R/ Yeah I considered as continuos load. 125%

 

[INGMRS]

My point

My point

Dears,


My specificaly doubt is about the resiult after to aplly the demand factors, because always the connected load is equal to the demand load (for this case).


That is my point.


Thanks a lot for your responses.


Regards,


Note: I Apologise for my poor English.

 

[jumper]

Note: I Apologise for my poor English.

Your English is fine. Easily understood.

 

[INGMRS]

Thanks

Thanks

Thanks,

Regards,

Your English is fine. Easily understood.

 

[charlie b]

My specificaly doubt is about the resiult after to aplly the demand factors, because always the connected load is equal to the demand load (for this case).

Take another look at my post #2. Your Excel file has some errors that are the cause of connected load being equal to demand load. You need to fix those errors and then look at the results.