Electrical Enclosure Heater Selection Guide

How to Prevent Premature Failure of Control Panel Components Due to Condensation

Why is a heater necessary?

Since control panels and their components are integral to the success of your facility, it is important to take every step possible to ensure their protection and longevity. When temperatures drop below the minimally acceptable range for electronics, the risk of condensation and eventually corrosion becomes eminent. Electrical enclosure heaters are designed to help protect your control panel components from the harmful effects of condensation and corrosion. In order to prevent humidity and condensation, the lowest temperature differential between room temperature and the enclosure interior must be 10° F+. For outdoor applications, the heating power requirement is doubled.

Determining the wattage required

To determine the required panel heater size, follow this equation: PH = (A x ΔT x k) – Pv 

PH = Required heating power for your application in Watts (W)
A = Exposed enclosure surface area square meters (m2).

ft² =m² * 10.764

m² = ft²/10.764

ΔT = Temperature differential between the desired minimum interior temperature and lowest possible external temperature of the enclosure in Kelvin (K), 1.8°F = 1°C = 1K   (ex. 36°F/1.8°F=20°C=20°K)

k = Heat transmission coefficient of the enclosure material used:

Stainless Steel: 3.7 W/m2K
Painted Steel: 5.5 W/m2K
Aluminum: 12 W/m2K
Polyester/Plastic: 3.5 W/m2K

Pv = Heating power generated by existing components (e.g. a transformer) in Watts (W)

**Note: For outdoor applications it is recommended to double the heating power.

Heaters in large control panels 

In larger control panel enclosures the use of more than one heater may be required.  This helps to normalize the temperature across the panel and reduces the risk of hot spots near sensitive components.

Selecting your electrical enclosure heater

Rittal Electrical Enclosure Heater Application

Electrical enclosure heaters are available from various manufacturers. Because of their attention to quality and performance, BgB Supply chooses to stock Rittal brand enclosure heaters.

Rittal’s panel heaters are the ideal way to regulate the internal conditions of your enclosure. The heaters are able to self-regulate their operation (only using energy when required) with their advanced PTC technology.  The added double quick-fit terminals and quick assembly system help reduce unnecessary labor costs.

Heaters with built-in fans operate at 110/230 volts, 50/60 Hz and are capable of generating thermal output of 250W, 400W and 800W from three models. Heaters without fans operate at 110/240 volts, 50/60 Hz and provide continual thermal output of 10 to 150 watts from 7 models. Various output ratings ensure that the correct thermal output is always available. Our 100W unit is the most common and most versatile of the Rittal line. In large enclosures it is easily doubled up for higher watt requirements. For precise temperature control, all the units can be fitted with an optional thermostat, temperature indicator/controller and a hygrostat to monitor humidity levels. If you need a Rittal heater that is not listed on our site submit a custom stocking request and we will order it for you.

Rittal Enclosure Heater Catalog Page

Rittal Enclosure Heater Sales Sheet