Space heater power supply for MV Switchgear

[NickParker]

Space heater power supply for MV Switchgear:
a) LV AC Control Power Transformers, located in a cubicle upstream of each main breaker.
b) From External power source say emergency 230V or from UPS.
What are the pros/cons of a) and b)? which one will you go for?

 

[waross]

Is this to maintain a minimum temperature to avoid malfunction at very low temperatures or an anti-condensation heater.
I have seen both types fitted to the same cubicle. Condensation may occur at any temperature and anti-condensation are typically supplied 50% of rated voltage and are left on at all times.
Space heaters cycle as needed.
Ours were fed from lighting transformers. (Option three?)

 

[dpc]

Unless this is an extreme low temp environment, using a UPS to power space heaters seems impractical and expensive. I've never seen it. I also question the need for separate CPT for each breaker to power the space heaters, but this is not as wild as powering from a UPS. As Bill says, we would normally power these from a normal AC panelboard.

 

[bacon4life]

I am a bit confused by having a CPT per breaker. Is that MV/LV like 15kV/120V or LV/LV like 480V/120V? Switchgear line-ups I am familiar with typically have a 25 kVA 15 kV/120-240V for in the aux cubicle for each HV/MV substation transformer coming into the MV switchgear.

One consideration for segregating normal AC between breaker cubicles is being able to completely de-energize a cubicle while working in a cubicle.