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GFI Protection on 480V, 1ph, 5kW space heater

GFI Protection on 480V, 1ph, 5kW space heater

GFI Protection on 480V, 1ph, 5kW space heater

(OP)
I am installing a 480V, single phase, 5kW space heater in a "hot box" around an above ground backflow.  Do I need to feed this heater with a 2 pole, 480V, GFI breaker?

RE: GFI Protection on 480V, 1ph, 5kW space heater

NO. But if you choose to, it should be less sensitive (30mA sensitivity) breaker desgined for equipment protection and not personnel protection.

RE: GFI Protection on 480V, 1ph, 5kW space heater

The 30 mA is for life saving. I think the second "0" dropped. Was probably meant to be 300 mA.

But I would use 30 mA. If using any at all.

Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: GFI Protection on 480V, 1ph, 5kW space heater

Skogs, On this side of the pond, 5mA is personnel protection and 30mA is equipment protection for things like heat tracing.  The 5mA is ±1mA and anything over 6mA is not considered suitable for personnel protection.  On the other hand, these are generally applied at the receptacle (outlet) and occasionally at the breaker; applying it at the breaker allows the natural leakage of the circuit to "pre-load" the GFCI with anywhere up to enough to cause a trip.  The 30mA devices are almost always breakers.

RE: GFI Protection on 480V, 1ph, 5kW space heater

Interesting - over here a 10mA RCD is used in higher risk environments and a 30mA RCD is the standard for personnel protection. 100mA is about the lowest used for equipment protection but there are quite a few variations of tripping current and response time, e.g. 100mA / 100ms is frequently used for equipment protection and is intended to grade with a downstream 30mA instantaneous RCD used for personnel protection.
 

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  Sometimes I only open my mouth to swap feet...

RE: GFI Protection on 480V, 1ph, 5kW space heater

I meant 30 mA as it is common for equipment GFP here in the USA. Personnel protection sensitivity is 4-6mA by Code as davidbeach pointed out.

I believe 300mA GFP are available. It all depends on normal "leakage" or capacitive current of the equipment and circuit. You want to beat that.

RE: GFI Protection on 480V, 1ph, 5kW space heater

Hmm.. Very interesting.

We have a big problem with 30 mA RCDs (as we call them) and nuisance tripping. Especially when there are VFDs involved. It may be because we have a higher voltage (230 V phase-ground). I think that our RCDs are specified somewhat like Must Trip > 30 mA and Must Not Trip < 18 mA.

I have been "saved" by 30 mA devices several times - I trust them too much.

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: GFI Protection on 480V, 1ph, 5kW space heater

I noticed, too late, that you actually have a 480 V installation. That's a lot for a 30 mA RCD.

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

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