Big Boy toys

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JDB3

Senior Member
Location
San Antonio, Texas
Bidding on a plan. Garage, shop, office area for big boy toys. Upstairs area will be finished out latter with full living quarters (with kitchen area) approximately 1300 square feet. Plans call for 3 wire 50 amp receptacle, 3 wire 30 amp receptacle in the shop area & 3 wire 50 amp receptacle outside.
Original plans indicate 200 amp service.

I am uneasy about a 200 amp service. How would you'll calculate the load with the 2 50 amp & 1 30 amp receptacles?
 
J

JDB3

Senior Member
Location
San Antonio, Texas
S o r r y. :slaphead:
I forgot to mention that there is going to be electric heat strips with heat pump outside.
A 3 ton (30 amp +/-) heat hump with 10kw heat strips back up & a 4 ton (40 amp +/-) heat pump with 15 kw heat strips back up.
He also noted a stub-out for a future shed.

Thanks
 
J

JDB3

Senior Member
Location
San Antonio, Texas
heat pump 30 amp x 240 volt = 7,200 7,200
heat pump 40 amp x 240 volt = 9,600 9,600
strip heat (back-up) 10kw = 10,000 @ 65% = 6,500
strip heat (back-up) 15kw = 15,000 @ 65% = 9,750
Heat pump & strip heat load =33,050 watts

33,050 watts / 240 volts = 137 amps for possible heating load ??
 
J

JDB3

Senior Member
Location
San Antonio, Texas
I was told that this guy started out as a residential electrician & is now a commercial electrician in California. I do not know his work experience in trade. Apparently he has not done residential work by the 2014 NEC (which Texas is under), due to the way circuits were drawn out.
I do not want to under size the service, and do not wish to do more than necessary.
With the possible heat load ( and yes, where this is to be built, there is a possibility that the heat pump & back-up heat strips will be running at the same time), is the reason I wanted some other thoughts on it.
Thanks again.
 
kwired

kwired

Electron manager
Location
NE Nebraska
JDB3 said:
S o r r y. :slaphead:
I forgot to mention that there is going to be electric heat strips with heat pump outside.
A 3 ton (30 amp +/-) heat hump with 10kw heat strips back up & a 4 ton (40 amp +/-) heat pump with 15 kw heat strips back up.
He also noted a stub-out for a future shed.

Thanks
Click to expand...

That is just a minor thing to forget to tell us.;)

The 50 amp receptacles likely have little impact though. Quite often they are for welders, and also quite often it is just one or two welders that may be moved from one place to another but never more then one is used at a time. Also unless in fabrication shop that has welder(s) going all the time these hobby shop welders can almost be disregarded (I said almost) in your load calculation. As long as there isn't significant voltage drop because of them, they don't have high enough duty cycle to be much factor.
 
kwired

kwired

Electron manager
Location
NE Nebraska
JDB3 said:
I was also concerned that one of the 50 amp receptacles (outside) might be used for a RV (but since it calls for a 3-wire 50 amp, I doubt it) ??
Click to expand...

Depending on what if any load you assigned the 50 amp outlets before - if you plug an RV in you lose whatever you you did account for and replace it with the RV load.

The RV will likely get you into overload situations easier then a welder will though because the welder is fairly limited cycle where RV may have continuous/near continuous load at times - especially the air conditioner.
 
Fulthrotl

Fulthrotl

~Autocorrect is My Worst Enema.~
Location
HB, CA (19 Hrs. 22 Min. from Winged Horses)
Occupation
E
JDB3 said:
I was also concerned that one of the 50 amp receptacles (outside) might be used for a RV (but since it calls for a 3-wire 50 amp, I doubt it) ??
Click to expand...

let's be realistic.... i've seen a 10,000 sq. ft. machine shop
running on 200 amps of 3ph. delta.
you just had to start the 25 hp leblond lathe first..... :lol:

most big boy toyboxes have a number of toy's, er, tools,
and they will be operated one at a time.

my little industrial park has 100 amps 3 phase to each unit.
there are three machine shops, several light manufacturing
concerns, and a wood shop. nobody has run out of juice.

unless he has plans for a 5 axis cnc machining center in the corner,
and a 50 horsepower shear in the other corner, relax and enjoy the job.
 
J

JDB3

Senior Member
Location
San Antonio, Texas
Good answers, but, a residence on 2nd floor of "toy room", with heating & cooling for both areas, full kitchen, etc. . I still am uneasy.

I had bid on another residence, that an uncle had built 200 amp service on a pole. They then were going to feed the house (204 amp load on 1st phase), later to finish out 2nd floor. Then from pole, feed water well & 20 x 40 work shop.

Uncle is going to wire it for them (I would not wire it, with just the 200 amp service) !
 
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