100 amp service from 200 amp for Tiny home


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Old 08-03-17, 12:19 PM
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100 amp service from 200 amp for Tiny home

Hi, im new here and I wanted to get some opinions on running about 70-80 feet of service wire from my homes 200 amp service breaker panel to a 100 amp service for a new tiny home project. I would need all the things a home needs like hot water heater, split heating and air unit, stove, washer and dryer. I've been told numerous types of wire but i wanted to see if the 2-2-2-4 SER aluminum service wire would work? Thanks in advance and hope you're all having a great day!
 
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Old 08-03-17, 01:40 PM
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SER can not be buried even in conduit. Better and probably cheaper is to use mobile home cable. Note using #2 your supplying breaker is limited to 90 amps but the breaker in the subpanel can be greater because it is only used as a disconnect switch.
338.12 Uses Not Permitted.
(A) Service-Entrance Cable. Service-entrance cable (SE) shall not be used under the following conditions or in the following locations:
(1) Where subject to physical damage unless protected in accordance with 230.50(A)
(2) Underground with or without a raceway
(3) For exterior branch circuits and feeder wiring unless the installation complies with the provisions of Part I of Article 225 and is supported in accordance with 334.30 or is used as messenger-supported wiring as permitted in Part II of Article 396
 
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Old 08-04-17, 07:39 AM
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The wire you need depends on whether the local authorities consider this a separate dwelling unit. As Ray said if you use #2 aluminum it is only good for 90A. Dwelling units require minimum of 100A so you would need to increase the size of the cable. Is the construction permitted as a dwelling or is it more portable like an RV?

Are either of the panels located inside the buildings?

You'll also need to do a demand load calculation on your house's service to determine if it has sufficient capacity to support the second home.
 
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Old 08-04-17, 11:10 AM
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Thanks so much for your reply and help ray2047!!
 
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Old 08-04-17, 11:15 AM
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Hi and thanks so much for your reply ibpooks! Both panels are inside the homes. The tiny home we are working on is a 12x40 lofted barn cabin. It can be moved but doesn't have wheels or anything where you can just go with it without major work to move it so I consider it a dwelling. If i may ask how do i do the load calculation of my current home? Thanks again!
 
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Old 08-04-17, 08:51 PM
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Just Google electrical load calculator.

Example: http://www.nojolt.com/load_calculations.shtml
 

Last edited by ray2047; 08-04-17 at 10:06 PM.
 

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