not be greater than the sum of the largest rating or setting of the branch-circuit short- circuit and ground-fault protective device provided with the industrial control panel, plus 125 percent of the full-load current rating of all resistance heating loads, plus the sum of the full-load currents of all other motors and apparatus that could be in operation at the same time.
Exception: Where one or more instantaneous trip circuit breakers or motor short-circuit protectors are used for motor branch-circuit short-circuit and ground-fault protection as permitted by 430.52(C), the procedure specified above for determining the maximum rating of the protective device for the circuit supplying the industrial control panel shall apply with the following provision: For the purpose of the calculation, each instantaneous trip circuit breaker or motor short-circuit protector shall be assumed to have a rating not exceeding the maximum percentage of motor full-load current permitted by Table 430.52 for the type of control panel supply circuit protective device employed.
Where no branch-circuit short-circuit and ground- fault protective device is provided with the industrial control panel for motor or combination of motor and non-motor loads, the rating or setting of the overcurrent protective device shall be based on 430.52 and 430.53, as applicable.
409.30 Disconnecting Means. Disconnecting means that supply motor loads shall comply with Part LX of Article 430.
409.60 Grounding. Multisection industrial control panels shall be bonded together with an equipment grounding conductor or an equivalent equipment grounding bus sized in accordance with Table 250.122. Equipment grounding conductors shall be connected to this equipment grounding bus or to an equipment grounding termination point provided in a single- section industrial control panel.
HI. Construction Specifications
409.100 Enclosures. Table 110.20 shall be used as the basis for selecting industrial control panel enclosures for use in specific locations other than hazardous (classified) locations. The enclosures are not intended to protect against conditions such as condensation,
icing, corrosion, or contamination that may occur within the enclosure or enter via the conduit or unsealed openings.
409.102 Busbars and Conductors. Industrial control panels utilizing busbars shall comply with 409.102(A) and (B).
(A) Support and Arrangement Busbars shall be pro- tected from physical damage and be held firmly in place.
(B) Phase Arrangement. The phase arrangement on 3- phase horizontal common power and vertical buses shall be A, B, C from front to back, top to bottom, or left to right, as viewed from the front of the industrial control panel. The B phase shall be that phase having the higher voltage to ground on 3-phase, 4-wire, delta- connected systems. Other busbar arrangements shall be permitted for additions to existing installations and shall be marked.
409.104 Wiring Space in Industrial Control Panels.
(A) General. Industrial control panel enclosures shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices, unless adequate space for this purpose is provided. The conductors shall not fill the wiring space at any cross section to more than 40 percent of the cross-sectional area of the space, and the