Switch Gear: Heat Loads

[ThermalRap]

Although there is a rule of thumb that all power to electrical/electronic devices is assumed to be lost as heat, I am calculating greatly elevated theoretical temperatures vs. empirical data. I believe the cause of this disparity is that the assumption is overly conservative for switch gear, and the like. For switch gear, not all power is lost as heat or else there would be no power to deliver downstream! Therefore, wouldn't it be smarter to account for dissipated heat by applying the efficiency rating (or, rather the inefficiencies) of the equipment? Surely, others have been down this road, as well. Your thoughts?

 

[Compositepro]

Switch gear will have minimal heat loss. Efficiency should be on the order of 99% or better. You will get a better qualified answer in the electric power distribution, or motors forum. But, some of those guys follow this forum as well.

 

[EnergyProfessional]

Unless you have transformers in that room, it really is negligible. It isn't even used in voltage drop calculations. Some minimal ventilation will be more than enough.

Unless of course the E-engineer greatly undersizes the wire and someone puts bolts into the fuse holders

 

[willard3]

Or you overload the switchgear or the conductors are aluminum and nobody has torqued the connections for a long time and etc.

 

[EnergyProfessional]

Maybe consider the cooling load of arcflashes?