Sub-panel wiring questions

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electrotuco

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I would appreciate for clarifying.
I want to add more outlets and light fixtures in to additionally builtrooms in the house.
It is no extra space in the main 100A panel.
I was going to add in the crawl space a sub-panle box: Siemens 8-Circuit 4-Space 125-Amp Main LugLoad Center, installing four dual single-pole 15A circuit breakers in it (twofor each phase).
This would give me eight 15A rated outputs to run eight # 16 cables tolights, outlets.
In the main panel I was going to install dual-pole 50A breaker (mainpanel has room only for this).
The plan was to use metal flex conduit to run four #8 wires to feedthat branch box Uinside ?? metal conduit).

Is my thinking is right.
I used online calculator table which results confirmed that 50A circuitbreaker is OK, 10 gauge GND wire in the cable is OK (going to a branch box witheight 15A rated outputs), but the threeconductors are specified as 6 gauge, not the 8 gauge that I was thinking. Thishappened due to correction factor per note ?Circuit is Branch Circuit thatsupplies multiple receptacles?, needs to follow 240.4(B) Devices Rated 800Amperes or Less. The conductors being protected are not part of a multi outletbranch circuit supplying receptacles for cord and- plug-connected portableloads?.and etc.
If do not use that special condition, the calculator says that 8 gagewires are OK.

Is my exercise is correct, should I consider an auxiliary box(8-Circuit 4-Space 125-Amp Main Lug Load) as
?Circuit is Branch Circuit that supplies multiple receptacles? and use6 gauge wires or I am mistaken and 8 gauge wires are OK?

 

George Stolz

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I am closing this thread, in accordance with the Forum rules. This Forum is intended to assist professional electricians, inspectors, engineers, and other members of the electrical industry in the performance of their job-related tasks. However, if you are not an electrician or an electrical contractor, then we are not permitted to help you perform your own electrical installation work.
 
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