ELECTRICAL DESIGN ANALYSIS vs. ELECTRICAL SCHEDULE OF LOADS

[Fel Flores]

Here in the Philippines, our electrical plans are required to be provided with the Electrical Design Analysis, Single-line Diagram and Schedule of Loads.

From my understanding, the electrical design analysis shows an "approximation" of the electrical loads. We get the total habitable area, multiply it by the corresponding VA/sq.m, add the kitchen equipment loads as well as the mechanical (HVAC) equipment loads.

while the electrical load schedule shows the more "detailed" rating and computations.

I have mall fit-out projects that has 3 power tapping points. These power tapping points are reflected on our Single-line Diagram.

However, the city engineering office commented on the electrical plans that since there are three power tapping points, there should be an electrical design analysis for each tapping point.

Is it really how it should be?

Hoping to get professional inputs

 

[GoldDigger]

Without such an analysis, at least a rudimentary one, you cannot be confident of how the power usage might be distributed among the three points.
If you provide overcurrent protection for each sufficient to protect the wires going to that power point (service?) then there would be safety risk in doing only an overall calculation, but you definitely run the risk that one point might not be able to provide power to all the loads that would be likely to connect the while leaving excess capacity at the others. That would be a problem to the occupant once the build is completed.

And if the responsible authority requires it, it does not really matter what we or the NEC think about that situation. :roll:

 

[RumRunner]

Here in the Philippines, our electrical plans are required to be provided with the Electrical Design Analysis, Single-line Diagram and Schedule of Loads.

From my understanding, the electrical design analysis shows an "approximation" of the electrical loads. We get the total habitable area, multiply it by the corresponding VA/sq.m, add the kitchen equipment loads as well as the mechanical (HVAC) equipment loads.

while the electrical load schedule shows the more "detailed" rating and computations.

I have mall fit-out projects that has 3 power tapping points. These power tapping points are reflected on our Single-line Diagram.

However, the city engineering office commented on the electrical plans that since there are three power tapping points, there should be an electrical design analysis for each tapping point.

Is it really how it should be?

Hoping to get professional inputs

Hi Fel
If I'm understanding you correctly, you are referring to power distribution block when you mention tapping points. The city engineer needs a detailed drawing on how you are going to accomplish these connection points. One line diagram will not cut it.

Are you going to make splices with split bolt connectors, distribution blocks or something else?

What I've done in the past was outsource these distribution blocks to a reputable mfg specializing in this electrical item. There is a company that makes this item: ILSCO Electric Co. Their product is distributed by Gordon Electric here in US. Other outfits make them too.

I know you are in the Philippines but you can request pdf format the specs, UL approval, test result and all pertinent data about an item you've chosen.
Enclose this info with the rest of your drawings to show to the city engineer.
You don't need the actual component at this point of plan check. They want some documentation.

In terms of analysis you mentioned, ILSCO will provide this too.
Google is your friend.

 

[Ingenieur]

my understanding
you have a main feeder
and 3 sub-feeds tapped off it (feeding 3 seperate areas)

you did a load calc for the main feeder based on the summed area (and equipment) of the 3

he wants a calc for each area
the 3 summed should equal the calc for the main feeder
he may want to see if the sub-feeds are adequate for the served load

 

[Fel Flores]

May I know how is it done there in the US?