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#83009 - 01/01/03 07:15 PM Diversity question  
sparky  Offline
Joined: Oct 2000
Posts: 5,311
hi all.

i've a question here , sort of a reoccuring one at that, any input appreciated.

A retiree or other such amature woodcrafter sets up shop in a detached garage.
The plan includes lathes, planners, drill presses, and all manner of woodworking machinery.

The load/feeder/panel are sized properly
(and then some for growth & VD) , yet the total places the incomming service as being inadeqaute per the demand load.

The obvious here is that the retiree/amature will only assume ONE machine @ a time, with little real impact.....

What would be your approach to this?

[Linked Image]

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#83010 - 01/01/03 07:27 PM Re: Diversity question  
Roger  Offline
Joined: May 2002
Posts: 1,716
Steve, I can only speak for my basement woodworking shop. With the exception of running a shop vac, or for those who own one, a true dust collection system, I never have more than one tool running at once. Of couse I work alone.


#83011 - 01/01/03 07:42 PM Re: Diversity question  
spyder  Offline
Joined: Oct 2002
Posts: 210
How many amps is our feeder to the garage? Are you mainly working alone?

#83012 - 01/01/03 09:08 PM Re: Diversity question  
sparky  Offline
Joined: Oct 2000
Posts: 5,311
the scenario is repetitive, yet academic.

would 220.21 apply here?

the 'retiree' could move out, and a commune of futon builders take up residence .... [Linked Image]

[This message has been edited by sparky (edited 01-01-2003).]

#83013 - 01/05/03 06:49 AM Re: Diversity question  
Scott35  Offline

Broom Pusher and
Joined: Oct 2000
Posts: 2,707
Anaheim, CA. USA

For this scenario, there are definitely two approaches!

First one is the "Per Structured Engineering" way of looking at it. By design default, the load calcs designate a service ampacity size, which would need to be met - so as far as "The Blind Lady Of EE" (like the blind justice lady), the service would require upgrading.

Second approach is the "Real Life" aspect!
Since there is only one person working on stuff, chances are two or more heavy load machines will not be driving out at near rated horsepower all the time. Even if this occured, it would not be an extended time, nor be done over and over. If this could become reality, then the scenario changes and the real world / real life aspect will indeed point towards service upgrade.

So, if this client wishes not to spend money on service upgrade and understands all that is regarding the complete scenario, it's simply a matter of annoyance if or when the main breaker trips.
As long as the scenario does not result in barbequed bus bars or Fried Insulation / Breakers AND this does not end up bringing down the Utility owned Power Transformer, this is a design issue - and (should be) compliant to minimal NEC reqirements.

This is stepping more into the Design / Engineering areas than code compliance - with the exception of the possibility of any INCREASE OF FLOOR SPACE (like a room addition or any new out buildings, which increase the basic requirements of a service).

Being a Residential situation, this makes things a bit different as to machinery. It's for only one person to use as a "Hobbiest", and the amount of time things are used fluctuates around when the neighbors are sleeping and when the Lunch + Dinner bells ring [Linked Image]

Now as to the future Commune of Futon Builders becoming the leasee or new owner of this location, this has no bearing towards the current "Client / Tenant's" requirements, nor do you need to design to reflect this.
When said cult of personnel occupy this location, the systems should be compliant (as per safety issues) prior to change of ownership. It is up to the new owner(s) to have the Electrical systems Engineered to meet their requirements.

In a typical "Shell" building, service size would be ample to "most tenants". Basic "per square feet" items are included, plus growth factors. Tenants with specific requirements (as to what they need for service size) require designs that include increased capacity - hence the difference between "A simple Electrical Systems Design" and "An Electrical Engineered System" becomes clear.

This message most likely is as clear as mud, so feel free to question away!!!

Scott s.e.t.

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

#83014 - 01/05/03 08:12 AM Re: Diversity question  
sparky  Offline
Joined: Oct 2000
Posts: 5,311
Actually quite clear Scott, thank you.

I have pursued option #2 a number of times,reading the customer thier 'electrical rights' as it were.
A notable amount of 'flicker factor' was explained also.

Being rural, the last such customer had an older direct burial 150A service, over 400' to the nearest pole. I say older in that DB is no longer in vogue here, so any update would be pvc.

Then there was another 200' to the shop/outbuilding.

This the poses a cost-benifit desicion to the customer, of considerable $$$ per upgrade...quite repetitive here.......

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