Cable sizing for Switchgear breaker

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car81

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I have a switchgear that I am feeding 125VDC power for its circuit breakers controls (lights, spring charging motor, etc..). The continuous current is about 3 amps, however, this current can spike up to lets say 70 amps very briefly when the breaker opens because of the trip coils and number of breakers. Is it ok to use a #12 AWG cable? Ampacity of this cable is about 27 Amps or so which is ok for the continuous current but is there a problem with those brief spikes in current? can the cable handle this. thanks.
 
The batteries feed a subpanel with a 125A main breaker, and from this subpanel, the switchgear will be fed with a 20 A breaker (inst. trip is usually 6-10 times the breaker size so breaker i assume breaker will not trip during the current spikes since it is only for less than a second)
 
car81 said:
The batteries feed a subpanel with a 125A main breaker, and from this subpanel, the switchgear will be fed with a 20 A breaker (inst. trip is usually 6-10 times the breaker size so breaker i assume breaker will not trip during the current spikes since it is only for less than a second)
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The charging motor draws the most current and typically for 5 seconds or so.
 
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