What is the dew point of KT busbar trunking systems (previous ranges and Canalis Evolution)?

The dew point is the temperature for which a device reaches 100% of humidity and generates the condensation phenomenon.

The dew point only depends on the parameters at the time of installation:

• Ambient air temperature
• Humidity % (RH) in ambient ai

The hotter the weather and the wetter the air during installation (e.g. in August), the more chance the dew point will be of being high (temperature at which 100% of humidity is reached => condensation).  The colder and drier the weather during installation (e.g. in November), the more the dew point will risk being low.

• Example: Mounting equipment at 20°C ambient temperature and 60% humidity, then move to 55°C ambient temperature before stopping the installation

At what temperature will condensation occur?

Mounting phase:
From Mollier's diagram:
Absolute humidity = Function (ambient air temperature) for various relative humidity ratios
=> absolute humidity = 0.009 Kg of water//kg of dry air

Operating phase:
Move from ambient air (near bars or enclosure) to 55°C
=> the volume of air around the conductors increases (constant pressure and increasing temperature)
=> the quantity of water remains constant in a larger volume of air
=> the relative humidity ratio decreases: 10% as per Mollier's diagram Installation

Shutdown phase:
Still as per Mollier's diagram, for a constant absolute humidity =0.009 Kg of water/kg of dry air

• - if ambient air moves to 20°C => the relative humidity ratio moves back to 60%
• - if ambient air moves to 12°C => the relative humidity ratio moves to 100 %

=>the dew point is reached so we get condensation

To estimate the dew point of a busbar trunking, we must:

• Know or estimate the ambient temperature and the relative humidity ratio during equipment mounting:
• Typical values are:
• ambient temperature = 20°C
• relative humidity ratio = 60%
• estimation of absolute humidity by reading on Mollier's diagram
• for estimated absolute humidity, read on Mollier's diagram the temperature for which a relative humidity ratio = 100% is reached

Released for:Schneider Electric Ireland