Exsisting 3phase 100amp 240v delta system.
Upgrade 3phase 150amp 240v delta system.

This service is underground and I have already requested a work order with the Utility Company. It appears the exsisting underground feeders are of a sufficient size and
will confirm with them.

The exsisting panel is rated for 150amps. There are:

2 pole 240v arc welder 30amp

3 phase 240v air compressor 50amp

3 phase 240v sub panel 60amp
The equipment from the
subpanel is feeding a
paint booth and uses
approximately 23amps

Interviewing the owner of the Auto Body Shop I was able to determine the typical use of the equipment on this service.
I used an amp probe to take readings at different times during the day to find out what the actual load was on the service. The load averaged between 20 and 60 amps evenly distributed between phases.

The new equipment will be 3 phase 230v 50amp breaker.

Would anyone be able to give me some feed back on whether or not I am correct on thinking this upgrade will handle the exsisting load and the new load. I am assuming 60amp exsisting plus 50amp max on new for a total of 110amps on the 150 amp service. 80% being 120amps.

Thanks for any help in advance.

2 pole 240v arc welder 30amp

3 phase 240v air compressor 50amp

3 phase 240v sub panel 60amp
The equipment from the
subpanel is feeding a
paint booth and uses
approximately 23amps




What about the loads from lighting & heat / cooling & ventilation & receptacles (microwave, etc)?

What you have adds up to 163A.... In Canada, If I am not mistaken, the service in a garage must be rated at least 100% (not 80%) of all loads

Also, what if they want to add equipment in the future?

A 150A panel should be the same price as a 200A panel...

They have service for other equipment.

Don't you have calculated loads in Canada?

The exsisting panel is 150 with a 100 breaker.

Any thoughts would be appreciated.

The ampmeter, is not going to give you the calcuated load.

dont want to bog this down with too many CEC references, but for a garage, there is a 10watts per square meter value from table 14, and based on 8-210(b) the loads described are "special loads" and as such the rating of the equipment must be used for service ampacity with demand factors permitted in other sections of the CEC. In other words, 150 amp service could be okay, depends on the loads on the sub panel,the square footage of the garage, and the nature of this new 230(?)volt 50amp breaker. Most likely a 200 amp service will be required, but that means new feeders, possibly existing conduit size could be a concern.

Unless it's a tiny ark welder 30 amps seems a bit low. Ark welding in an auto body shop is not an acceptable repair by todays standards. Are you sure it was not a MIG welder? I could see the nameplate on that being 30a.

What do you mean they have service for other equipment?
Is there is 2 services for the same unit and one service your talking about is only for the equipment you listed?

Besides lighting, office, breakroom, bathroom, HVAC, there are receptacles in the shop? Is there some kind of exhaust fans in the shop? Things might be used like battery chargers, power tools, hydralic pumps, stud welder, portable heaters, work lights, fans, resporator pumps, and even computers.

Loads to come might be a frame rack, spot welder, plasma cutter, TIG welder, paint mixer, etc.

Paint booths have lighting, a large fan(s), and a heater that can bake the paint. 23 amps sounds a bit low for FLA.

This might not be a paint booth for cars, just for making parts look new.

I appreciate everyones input and maybe I'm not making the circumstances clear enough. I will try again here.

There are two services to the building. It is an exsisting Body Shop that has been in business for many years. The single phase 200amp service handles most of the electrical requirements such as general lighting and power.

The three phase system only handles the equipment I mentioned and the commercial HVAC company wants to install a 3phase, 42amp, 230volt unit. The name plate says max. 50amp overcurrent protection per phone conversation with the HVAC contractor.

I have performed actual readings several times during the day with confirmation from the owner who is completely hands on with regard to equipment use as to when what equipment is operated. The load is constantly 20 to 60 amps throughout the day on the 3 phase service.

The Utility company has already given the okay to perform upgrade however I wanted to confim that with the additional load of the HVAC system would the demand be within tolerance of a 150amp service upgrade from 100amp.

Therefore:

Would anyone be able to give me some feed back on whether or not I am correct on thinking this upgrade will handle the exsisting load and the new load. I am assuming 60amp exsisting plus 50amp max on new for a total of 110amps on the 150 amp service. 80% being 120amps.

Thanks again and I hope this clarifies my situation.

Let me try my math with your numbers.

Largest load air compressor 50 amps x 1.25 = 62.5
Welder 30 amps
Paint booth 23 amps
RTU 42 amps
Total 157.5 amps

I don't believe you can derate the other loads.

Thank you for your input Active 1.

Does anyone else agree/disagree.

I was under the impression that if I have an actual sevice load investigated that that takes precedent over calculated load. Therefore :
60amp exsisting plus 50amp max on new for a total of
110amps on the 150 amp service. 80% being 120amps.
If this is acceptable it would save the customer the
installation of a new panel and a 200amp upgrade which the
exsisting service lateral and meter could handle according
to the Utility Company.

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:

1. Compressor: 50 FLA - Largest Motor: 50 X 1.25 = 62.5 Amps. With LCL: 62.5 X 1.25 = 78.125 Amps.
2. MIG Welder: 30 Amps.
3. 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

Thanks for the email below. To answer your question about the Main breaker - It is a 150amp panel so I just assumed that I would be able to obtain a 150a breaker. I hadn't investigated whether or not it is available. The new HVAC equipment is for cooling only - fyi. The air compressor's I would have to say are non continuous as they are cycling on and off with about 20min off and 5 minutes on. The spray booth is definitely a continous load. The heaters which are controlled by this load are gas but the 23 amps is related equipment such as paint mixers which are part of the booth. I see the concern for an overload leading to a bad paint job and I think that that will make it easier for the owner to swallow the larger service...and yes I understand that that is the only code compliant option, therefore my only option as the installer. With regard to the upgrade the tap box has lateralls coming into it that are sized for 400amp (according to the Utility Company). I'll just need to run new taps to the meter and I'll plan on replacing the panel with 225a if that is standard stock in our area.
Thank you for the insight to the Delta system as well. I work almost entirely with single phase and I could ask several questions for clarification on this type of service.

If anyone has further thoughts please let me know.

__________________________________________________________


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:

1. Compressor: 50 FLA - Largest Motor: 50 X 1.25 = 62.5 Amps. With LCL: 62.5 X 1.25 = 78.125 Amps.
2. MIG Welder: 30 Amps.
3. 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.

BobV3CORP:



Feel free to fire away with your questions!

Scott

BTW, glad we were of assistance with this Service Upgrade.

Commercial three phase service? Possibly with a meter that registers peak demand? Any reason that 220.35 is not an option here?

-Jon