Space Heater Requirement

It might be helpful if we new what units h,W and D are? inches, yards,meters cm's?

Let me take a wild guess on the dimensional units as being the much maligned Czech stopa of 1759. This is critical to know because this will be placed in an old coal mine outside of Prague.

The units are in mm.

Heated DB? That's new to me.

Its freakin hot where I ply my trade. Surely the board would be self heating.

Live and learn I guess

An internet search on this subject was futile (for me anyway) I'd like to see some examples.

Yeah that sounds fine to me...

Impossible to tell. You need to know the lowest possible ambient temperature OUTSIDE of the box, the surface area of the box that is exposed to dissipate or absorb heat, the material that the enclosure is made of, the the lowest possible heat rejection of all of the devices inside of it. Do you know any of that?

For example, a 50W heater might work fine if you are using a fiberglass enclosure in the tropics, but will be woefully inadequate if you have a stainless steel enclosure in Norway. Or if the power is always on and the breakers are always carrying current, they will be rejecting heat and contributing to keeping the enclosure warm. But if you intend to protect the enclosure components when they are powered down (assuming separate power for the heater of course), then ALL of the necessary heat has to come from the heater.

Without all of that information, you can only guess, but guesses are useful in sports, gambling and politics, not engineering.

Thanks a lot. i am sorry for not providing that info before.

the lowest possible ambient temperature is 15.6 Degree Celsius. the real surface area of the enclosure is 10.18 meter square. the enclosure is made of sheet steel.the total power dissipated by the components (maximum) 894W.

i want to protect the enclosure components when they are powered down.

OK, good. Now take you data and plug it into the heater calculator at this website:

http://www.rittal-corp.com/products/index.cfm?n1ID=4&n2ID=20&n3ID=33

When it gets to where it asks for heat dissipation from internal components, say zero, because you want to heat it when everything is off.

Just don't forget that if you kill power to the heater, it can't work! I know it seems obvious but believe it or not it's a common mistake.

thank you Mr. J,

i have looked into Rittal Calculator. but the problem is they dont have that particular enclosure size which i have mentioned in my query. other than that it pretty much gave an idea as how to calculate .

What is your lacation on the globe? What is the average humidity in your local? What is the average percipitation? Is the location of this panel board in a building with addiquite ventilation? Does the building have a climate control for personel?

All these factors are the derivitives of your question.

For a simple answer to your question, if this is in a controled climate building, a 100watt heat element, mounted in its own enclosure for protection, with a circulating fan will help help keep the inside air dry of moisture. If the fan enclosure is mounted on the side of the cabinate, say the bottom corner behind the door, you can vent this air to circulate and out the adjasent top corner side for positive air flow. You would only need a small 12v or 24v fan no more the 25mm to 30mm dia.

Good luck, 8-) Maximo

Location :- Tamilnadu ( south India)

Avg Humidity :- 100%

avg Precipitation:- no idea

panel board in Building with adequate ventilation :- yes

Does building have a climate control for personnel? ofcourse.

is 100W really necessary? i have provided 50W without any fan (natural convection). i thought the surface of the panel would dissipate all the heat.

GA JRaef

However....there are no heaters in DBs in this part of the tropics. Aircon sure, fried geckos absolutley....