230.7 of the Code

[Dean83169]

Here is my question. If I have a 200 amp overhead meter main with dual 100's in it and I install an outdoor 200 amp transfer switch with a service disconnect in it, Can I install a 2" nipple between the panel and xfer switch; and run the service wire from the meter to the xfer switch; then load out of the xfer switch and through the nipple to re feed the dual 100's? Someone was saying I couldnt due to the fact I have fused and unfused wiring in the same raceway but its not a cable or a raceway, its a 2" x 4" nipple! They also stated I cant due to the fact that the load isnt considered service equipment and it runs through the same nipple as the service conductors. My theory is its all the same within the two cabinets since the load is ultimately protected by the two 100 amp breakers.

 

[Volta]

Here is my question. If I have a 200 amp overhead meter main with dual 100's in it and I install an outdoor 200 amp transfer switch with a service disconnect in it, Can I install a 2" nipple between the panel and xfer switch; and run the service wire from the meter to the xfer switch; then load out of the xfer switch and through the nipple to re feed the dual 100's? Someone was saying I couldnt due to the fact I have fused and unfused wiring in the same raceway but its not a cable or a raceway, its a 2" x 4" nipple! They also stated I cant due to the fact that the load isnt considered service equipment and it runs through the same nipple as the service conductors. My theory is its all the same within the two cabinets since the load is ultimately protected by the two 100 amp breakers.

A little on the confusing side. How many panels? Are the 100 amp breakers in the dual meter base?

But no. A nipple is a raceway.

(4) Where conduit or tubing nipples having a maximum length not to exceed 600 mm (24 in.) are installed between boxes, cabinets, and similar enclosures, the nipples shall be permitted to be filled to 60 percent of their total cross-sectional area, and 310.15(B)(3)(a) adjustment factors need not apply to this condition.

Now, fused and unfused conductors can generally be mixed, but not service and non-service.

Other Conductors in Raceway or Cable. Conductors other than service conductors shall not be installed in the same service raceway or service cable.

 

[augie47]

agree with Volta and others... can't mix service (unprotected) and non-service (OCP protected) in same raceway including nipples. Can you put two nipples in ?

 

[George Stolz]

Very confusing description. The easiest test is stated above; fused and unfused conductors cannot share the same raceway, even for an inch.

 

[kwired]

Other than the nipple issue that has been covered, just how are you planning to come from a "meter-main" to a transfer switch, then back to the "meter main" unless you are modifying the design of the meter-main? And if you modify it you may be rejected on 110.3(B).