Let me take a stab at this one.
First off, it appears the reason for the Service Upgrade is to accommodate the new HVAC Package, in addition to the existing loads on the original Service.
A point must be made regarding Non-Coincidental Loads and Non-Continuous Loads, which are connected to this Service.
I do not see many Non-Coincidental Loads, but I do see several Non-Continuous Loads running.
A Non-Coincidental Load may be the MIG Welder - as it could be used at any time, or may not be used for weeks at a time.
When it's used, it will not be drawing FLA for very long - only for a brief amount of time - like 5 to 10 minutes, then idles for a few minutes, then maybe peak for an additional 5 minutes, then back to idle.
Non-Continuous Loads may include the pre mentioned MIG Welder, and the Air Compressor.
If there are a lot of Air Powered Tools running constantly, the Air Compressor would run continuously to keep the Tank pressurized.
If the Compressor runs intermittently, this would not be a Continuous Load, and therefore not need to be figured with the 125% LCL adder
(
"LCL" = Long Continuous Load - basically, something that runs for 3 Hours or more )
The Spray Booth
_MAY_ qualify as an LCL - all depends on if it's possible for the Booth to be used for 3 Hours or more (180 Minutes and longer), at the rated load of 23 Amps, at any time.
I can see this being possible, so my suggestion is to rate it as an LCL - making it's Load 28.75 Amps.
As the O.P. mentioned, there is a separate Service for General Lighting and Power - the 120/240V 1Ø 3 Wire 200 Amp Service, so do we need to also include General Lighting and Receptacles loads to this new Service? Not likely, and I would hope no one attempted to install L-N Loads to this Service.
BTW, The reason for the "Dual Services" is due to the use of a Delta System. This is very common in my areas.
One Service (with its own 240V 1 stator kWH Meter) for "Lighting", which is a 120/240V 1Ø 3 Wire Service, derived either from:
* Line A & B off of the "Center" of the Delta 4 Wire Array,
or,
* From a stand-alone 1 Phase Transformer.
The "Other" Service (with its own 240V 1 stator kWH Meter), for "Power", which is a 240V 3Ø 3 Wire Service, derived from the Delta Transformer Setup.
-------------------------------------------------------------------------------
Calculations:
* New Load;
The new HVAC Package is likely to become an LCL at some point in time - either during the warmest days, or the coldest days
*(
* If this is a Heat Pump, then cold days apply)
The RLA (Rated Load Amperes) of this Package Unit = 42 Amps.
With an LCL Adder, the adjusted Load is now 52.5 Amps.
* Existing Loads:
- Compressor: 50 FLA - Largest Motor: 50 X 1.25 = 62.5 Amps. With LCL: 62.5 X 1.25 = 78.125 Amps.
- MIG Welder: 30 Amps.
- Spray Booth: 23 Amps recorded. With LCL: 28.75 Amps.
Subtotals for Existing Loads:
* Total NON-CONTINUOUS LOAD (at 100%): 115.5 Amps
* Total CONTINUOUS LOAD (+ 125% of CONT. LOAD): 21.375 Amps (round down to 21 Amps)
* Total for EXISTING LOAD: 136.5 Amps
------------------------------------------------------------
------------------------------------------------------------
Totals for New and Existing Loads:
1: Total NON-CONTINUOUS LOAD (at 100%):
* Existing: 115.5 Amps,
* New: 42.0 Amps,
* Calculated NON-CONTINUOUS LOAD: 157.5 Amps
2: Total CONTINUOUS LOAD (+ 125% of CONT. LOAD):
* Existing: 21.0 Amps,
* New: 10.5 Amps,
* Calculated CONTINUOUS LOAD: 31.5 Amps
3: Total DESIGNED LOAD CALCULATED (All Loads + LCL):
* NON-CONTINUOUS LOAD: 157.5 Amps,
* CONTINUOUS LOAD: 31.5 Amps,
* DESIGNED LOAD: 189 Amps (¹)
*** (¹): If the Air Compressor is NOT an LCL, then the total DESIGN LOAD would be 174 Amps (173.75 Amps- rounded up).
-----------------------------------------------------------
-----------------------------------------------------------
Conclusion:
It may be suggested that you consider the Upgrade to be 200 Amp - or possibly 225 Amp Service.
This will allow for some small future installations, or if the Client ever changes a piece of equipment out for something with a higher load rating.
Also, as pointed out, there's very little difference in Price between a 150 Amp Service and a 200 Amp Service, plus the 200 Amp Service is likely to be readily available.
Am I correct to say that the Existing Service is rated for 150 Amps, only that it has a 100/3 Main Disconnect mounted in it?
If yes, where you planning to just swap the 100/3 with a 150/3, or upgrade the entire Panel?
If you plan to swap the Main Breaker:
* Will you be able to install a 225 Amp frame in the Panel? (The original frame is likely a 100 Amp frame size, whereas the 150 Amp breaker will be at least of a 225 Amp Frame size)
* Will the lugs line up correctly?
* Will you be able to locate the 150/3 without too much trouble - or paying too many $$$?
(What brand is the equipment)
* Will the original Service Feeders be adequately sized for the designed Load, and will they be able to land on the lugs properly?
* Will you need to increase the size of the Grounding Electrode System, if the Service Feeders are increased in size?
To sum things up here, it appears that the existing loads were exceeding the rating of the Main Disconnect - as viewed from the standpoint of NON-CONTINUOUS LOADS and CONTINUOUS LOADS.
The reason the Main _MAY HAVE NOT_ tripped is these loads are kind of NON-COINCIDENTAL; and maybe one of the pieces of equipment was recently installed or upgraded.
Overloading + tripping due to Overload may have not yet appeared, or maybe it did - "Just Happened Once Or Twice" is a very common "Disclaimer" mentioned by some people.
It's up to you, as far as what you are planning to do.
Keep in mind, the values I give in this thread would be "Per Design Criteria", as opposed to what would be recorded per an Ammeter or from Nameplate Values alone.
In any case, don't open yourself up to any issues in the future, like:
* Installing an inadequately sized service,
* Main Breaker trips often - bringing down production / increased costs from having to re-do a Paint Job,
* Damaged equipment due to low voltage, main tripping, or low air pressure (pneumatic equipment),
* Other lovely Client issues.
If costs are the only motivating key item here, be sure to justify what is real to what is penny pinching.
What is the total cost difference between an upgrade to 150 Amps, and an upgrade to 200 Amps or 225 Amps?
The Client may have not even considered future installations, or the possibility for loss of production due to inadequate service size - or maybe it means nothing to them!
Good luck on this Project.
Let us know the outcome + what responses you have to my questions.
Scott
