Already a subscriber? 
MADCAD.com Free Trial
Sign up for a 3 day free trial to explore the MADCAD.com interface, PLUS access the
2009 International Building Code to see how it all works.
If you like to setup a quick demo, let us know at support@madcad.com
or +1 800.798.9296 and we will be happy to schedule a webinar for you.
Security check
Please login to your personal account to use this feature.
Please login to your authorized staff account to use this feature.
Are you sure you want to empty the cart?
PD IEC TR 60890:2022 A method of temperature-rise verification of low-voltage switchgear and controlgear assemblies by calculation, 2022
- undefined
- CONTENTS
- FOREWORD
- INTRODUCTION
- 1 Scope
- 2 Normative references
- 3 Terms and definitions
- 4 Verification conditions
- 5 Calculation method [Go to Page]
- 5.1 Assumptions made in this calculation
- 5.2 Necessary information
- 5.3 Calculation procedure [Go to Page]
- 5.3.1 General
- 5.3.2 Determination of the effective cooling surface Ae of the enclosure
- 5.3.3 Determination of the internal temperature-rise Δt0,5 of the air at mid-height of the enclosure
- 5.3.4 Determination of the internal temperature-rise Δt1,0 of air at the top of the enclosure
- 5.3.5 Characteristic curve for temperature-rise of air inside enclosure
- Figures [Go to Page]
- Figure 1 – Temperature-rise characteristic curve for enclosures with Ae exceeding 1,25 m2
- 5.4 Maximum internal air temperature limits
- 6 Further considerations [Go to Page]
- 6.1 General
- 6.2 Guidance on the effects of an uneven power distribution
- Figure 2 – Temperature-rise characteristic curve for enclosures with Ae not exceeding 1,25 m2
- 6.3 Guidance on the additional temperature-rise effect due to solar radiation
- 7 Evaluation of the design
- Tables [Go to Page]
- Table 1 – Method of calculation, application, formulas and characteristics
- Table 2 – Symbols, units and designations
- Table 3 – Surface factor b according to the type of installation
- Table 4 – Factor d for enclosures without ventilation openings and with an effective cooling surface Ae > 1,25 m2
- Table 5 – Factor d for enclosures with ventilation openings and an effective cooling surface Ae > 1,25 m2
- Figure 3 – Enclosure constant k for enclosures without ventilation openings, with an effective cooling surface Ae > 1,25 m2
- Table 6 – Equation for Figure 3
- Figure 4 – Temperature distribution factor c for enclosures without ventilation openings and with an effective cooling surface Ae > 1,25 m2
- Table 7 – Equations for Figure 4
- Figure 5 – Enclosure constant k for enclosures with ventilation openings and an effective cooling surface Ae > 1,25 m2
- Table 8 – Equations for Figure 5
- Figure 6 – Temperature distribution factor c for enclosures with ventilation openings and an effective cooling surface Ae > 1,25 m2
- Figure 7 – Enclosure constant k for enclosures without ventilation openings and with an effective cooling surface Ae ≤ 1,25 m2
- Table 9 – Equations for Figure 6
- Figure 8 – Temperature distribution factor c for enclosures without ventilation openings and with an effective cooling surface Ae ≤ 1,25 m2
- Table 10 – Equation for Figure 7
- Table 11 – Equation for Figure 8
- Figure 9 – Calculation of temperature-rise of air inside enclosures
- Annexes [Go to Page]
- Annex A (informative) Examples for the calculation of the temperature-rise of air inside enclosures [Go to Page]
- A.1 Example 1
- Figure A.1 – Example 1, calculation for an enclosure with exposed side faces without ventilation openings and without internal horizontal partitions
- Figure A.2 – Example 1, calculation for a single enclosure [Go to Page]
- A.2 Example 2
- Figure A.3 – Example 2, calculation for an enclosure for wall-mounting with ventilation openings
- Figure A.4 – Example 2, calculation for one enclosure half
- Figure A.5 – Example 2, calculation for an enclosure for wall-mounting with ventilation openings
- Annex B (informative) Guidance on the effects of an uneven power distribution [Go to Page]
- B.1 Horizontal partition
- B.2 Calculation of internal air temperature-rise for assemblies with ventilation openings with even power distribution and less than 50 % perforation in horizontal partitions
- Figure B.1 – Examples of assemblies with horizontal partitions [Go to Page]
- B.3 Calculation of internal air temperature-rise with an uneven power distribution
- Figure B.2 – Temperature-rise verification of a higher-power circuit
- Annex C (informative) Guidance on the additional temperature-rise effect due to solar radiation [Go to Page]
- C.1 General
- C.2 Solar radiation phenomena
- Figure C.1 – Solar radiation phenomena [Go to Page]
- C.3 Solar radiation – consequences for thermal calculation
- Figure C.2 – Interpolation curve
- Table C.1 – Approximate solar absorption radiation coefficients (according to colour) [Go to Page]
- C.4 Solar radiation of enclosures with air ventilation openings
- Annex D (informative) Guidance on the effect of different enclosure materials, construction and finishes [Go to Page]
- D.1 General
- D.2 Validity criteria
- D.3 Material of enclosure
- D.4 Results
- Figure D.1 – Results of comparison tests
- Annex E (informative) Guidance on the effects of different natural ventilation arrangements
- Figure E.1 – Examples of crossing diagonal installation
- Figure E.2 – Effect of additional filters
- Annex F (informative) Guidance on forced ventilation management [Go to Page]
- F.1 General
- F.2 Forced ventilation installation system
- F.3 Installation considerations
- Figure F.1 – Examples of forced ventilation arrangements
- Annex G (informative) Power loss values calculation [Go to Page]
- G.1 General
- G.2 Power losses of low-voltage switchgear and controlgear
- G.3 Power losses of conductors connecting low-voltage switchgear and controlgear
- G.4 Power losses of busbars
- G.5 Power losses of electronic devices
- Annex H (informative) Guidance on the impact of an adjacent wallon the assembly cooling surfaces
- Figure H.1 – Wall-mounted assembly
- Figure H.2 – Floor-standing assembly
- Annex I (informative) Operating current and power loss of copper conductors
- Table I.1 – Operating current and power loss of single-core copper cables with a permissible conductor temperature of 70 °C (ambient temperature insidethe enclosure: 55 °C)
- Table I.2 – Reduction factor k1 for cables with a permissible conductor temperature of 70 °C (extract from IEC 60364-5-52:2009, Table B.52.14)
- Table I.3 – Operating current and power loss of bare copper bars with rectangular cross-section, run horizontally and arranged with their largest face vertical, for DC and AC frequencies 16 2/3 Hz, 50 Hz to 60 Hz (ambient temperature inside the enclosure: 55 °C, temperature of the conductor 70 °C)
- Table I.4 – Factor k4 for different temperatures ofthe air inside the enclosure and/or for the conductors
- Annex J (informative) Guidance to magnetic and eddy-current power losses
- Figure J.1 – Power losses distribution for differentgland plates with the same rating
- Annex K (informative) Forced ventilation airflow calculation [Go to Page]
- K.1 General
- K.2 Ventilation airflow calculation
- Table K.1 – Factor k for altitudes above sea level
- Bibliography [Go to Page]
