ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Recent Posts
Continuous load
by HotLine1 - 03/08/23 02:11 PM
How's all our Non-US folks doing?
by dsk - 03/08/23 11:56 AM
Old Computers?
by Bill Addiss - 03/04/23 05:06 PM
New in the Gallery:
Burger King crown sillyness
Burger King crown sillyness
by wa2ise, December 11
240/208 to a house
240/208 to a house
by wa2ise, October 9
Who's Online Now
0 members (), 21 guests, and 13 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Joined: Nov 2001
Posts: 4
wirenut Offline OP
Junior Member
What size is the new service?

40x60 building, an old shoe store in a mini-mall that is turning into a sandwich shop like a subway.

Existing service is 200 amp 240/120 volt single phase.

Existing circuits:
1. 2 lighting circuits
a. (1) lighting circuit with 6 4x4 lay-ins at 40 watts each.
b. (2) lighting circuit with 5 4x4 lay-ins
at 40 watts each.
2. One sign circuit
3. 8 general recs
4. One a/c unit (compressor 8.5 amps at 240 volts and condenser fan at 2.4 at 240 volts)
5. Heat strips and air handler ( Heat 8.5KW at 240 volts and blower motor 4.5 amps at 240 volts)
NOTE- all above equipment to stay in the sandwich shop.
1) New equipment list from blueprints
A. New a/c unit (compressor 17.5 amps at 240 volts and condenser fan at 2.6 at 240 volts
B. New Heat and air handler (Heat 24KW at 240 volts and blower motor 10.5 amps at 240 volts

C. New kitchen equipment in the new kitchen.
Sandwich cutter: 2640 watts, all equipment is 120 volts.
3-door REG: 1440 watts
toaster A : 900 watts
toaster B : 900 watts
slicer: 300 watts
processor: 840 watts
Microwave: 1800 watts
cola machine: 2400 watts
Ice machine: 420 watts

D. Circuits that require a 20 amp circuit to each equipment, all eqiupment is 120 volts. Not in kicthen area.
Display case: 1236 watts
soup cooker A: 720 watts
soup cooker B: 720 watts
Cash register A: 300 watts
Cash register B: 300 watts
computer: 300 watts
E. 5 new general recs.
F. Additional sign at front door with "OPEN" on it. 1200 watts
G. New hot water heat at 13KW at 240 volts

1. What size is the new service for the Sandwich Shop and how did you come up with your load figure and where in the code. Can you show how you did it?

2. Can I use a AMP Probe to get the existing load of the existing service then apply it the new service calculation? And if, so, how do apply it in the calculation?

And if this is a yes, can I use the AMP Probe on all existing service when it's hard to count all the existing circuits up and their loads? How would you do this if you were going to add more circuits that might affect the existing service size, please explain..Thanks

No heat pumps.
All the a/c units, heat strips and air handler motors is from name plate ratings conveted to watts to determine the load on the service. The kitchen equipment, etc was conveted to watts from their Va ratings from the blueprints on the new equipment schedule.

[This message has been edited by wirenut (edited 11-25-2001).]

Joined: Oct 2000
Posts: 2,722
Broom Pusher and

My suggestion to you is to do a complete Load Calculation for this location, based on what will be used under the new Tenant.

You could do a simple load calc to verify the existing load / demands, which would be helpful to submit to the Utility Company and the Building Department to describe the need [possible] for an increased service size.
The Utility people should have a copy of the original load calcs for the existing service, so maybe they can submit a copy to you.

Anyhow, just quickly looking at your description, it sure looks like an increased service size may be needed [???].
Your load calcs will determine if this will be needed or not.

When doing the load calcs, use the Volt-Ampere rating of "Non-Linear" equipment, rather than the rated wattage.
Looks like the only True Power loads you have listed are 2 toasters, the water heater, and possibly the HVAC heat strips [if the HVAC is a heat pump, then they are most likely going to use Apparent Power].
All other loads are Apparent Power loads.

The True Power loads can be figured as Watts [or KiloWatts - "KW"]. These loads will draw a fixed amount of Amperage at a fixed Voltage, at 100% Power Factor [or very, very close to 100% PF].
In other words, if you have a True Power load of 120 Watts at 120 Volts, the Amperage will be 1 amp.

The Apparent Power loads should be figured as Volt-Amps [or KiloVolt-Amps - "KVA"]. These loads will draw more current at a fixed voltage than what is shown in wattage on the nameplate [or other documentation]. The level of current will depend on the Power Factor.
In other words, the equipment may list a True Power consumption of 100 watts @ 120 VAC [which would equal out to 0.84 amps @ 120 VAC], but in reality it could draw 1.0 to 1.5 amps @ 120 VAC. If the current drawn was 1.5 amps, the Apparent Power would be 180 Volt-Amps [VA].

Part of the Power in the complete Apparent Power figure is the True Power [the wattage], the remainder is the Reactive Power [VAR].

I rambled all this baloney to you so you would understand the differences in ratings.

Best to get name plate ratings of FLA [Full Load Amperes] from the Equipment to be installed, then use these ratings in your load calcs.

Your load calcs will need to be done as would be figured on any new service.
You will not have too much to rely on from the existing load calcs, since this T.I. consists of a new type of occupant. If you were simply adding more to the existing shoe store, then the original load calcs and demands could be implemented.

Take note of Load Calc descriptions in NEC Article 220, then see the examples given in the back of the code book [Appendix D].

This is as much help I can possibly pass on - outside of doing the calcs myself! [Linked Image]

If you have experience with Spreadsheets - such as Lotus 1,2,3 or Excel, you can create a quick and dirty spreadsheet for Load Calcs, then fill it out and print it for Utility Engineers and the Building Department / Electrical Inspector.

I wouldn't see any way this project could have gone through plancheck without some type of load schedule! Be it a NEC type load calculation form, panel schedules, or both.

Let me know if you have questions or comments.

Scott SET

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
Joined: Nov 2001
Posts: 4
wirenut Offline OP
Junior Member
No heat pumps.
All the a/c units, heat strips and air handler motors is from name plate ratings conveted to watts to determine the load on the service. The kitchen equipment, etc was conveted to watts from their Va ratings from the blueprints on the new equipment schedule.

Joined: Nov 2001
Posts: 4
wirenut Offline OP
Junior Member
Another question...............

The hot water heater, do I include it with kitchen equipment. It will be in the kitchen area in the back, it's a 50 gallon, 13KW 240 volts.

What if the water was in the ceiling? Would it be included in the kitchen equipment?


Link Copied to Clipboard

Tools for Electricians
Tools for Electricians

* * * * * * *
2023 National Electrical Code (NEC)
2023 NEC Now Available!
* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman


Member Spotlight
Minneapolis, MN, USA
Posts: 21
Joined: September 2019
Top Posters(30 Days)
triple 2
dsk 1
Popular Topics(Views)
304,924 Are you busy
233,346 Re: Forum
218,068 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5