Insulation coordination for Switchgear and Assembly as per IEC 60664

Nominal Voltage Ue Line to Neutral	Uimp for Overvoltage category — I	Uimp for Overvoltage category — II	Uimp for Overvoltage category — III	Uimp for Overvoltage category — IV
Vph – 50	330 V	500 V	800 V	1500 V
Vph – 100	500 V	800 V	1500 V	2500 V
Vph – 150	800 V	1500 V	2500 V	4000 V
Vph – 300	1500 V	2500 V	4000 V	6000 V
Vph – 600	2500 V	4000 V	6000 V	8000 V
Vph – 1000	4000 V	6000 V	8000 V	12000 V

Nominal Voltage
Ue
Line to Neutral

Uimp for
Overvoltage
category — I

Uimp for
Overvoltage
category — II

Uimp for
Overvoltage
category — III

Uimp for
Overvoltage
category — IV

Vph – 50

330 V

500 V

800 V

1500 V

Vph – 100

500 V

800 V

1500 V

2500 V

Vph – 150

800 V

1500 V

2500 V

4000 V

Vph – 300

1500 V

2500 V

4000 V

6000 V

Vph – 600

2500 V

4000 V

6000 V

8000 V

Vph – 1000

4000 V

6000 V

8000 V

12000 V

Impulse withstand category	Required Impulse withstand voltage	Equipment in category
Cat – I (low impulse voltage)	1.5 KV	Sensitive electronic equipment – Eg: TV, Laptop, Electronic Equipments
Cat – II (normal impulse voltage)	2.5 KV	Domestic appliances – Eg : Washing Machine, Fridge,
Cat – III (high impulse voltage)	4 KV	Main Distribution Boards
Cat – IV (very high impulse voltage)	6 KV	Near the Energy Meter

Impulse
withstand
category

Required
Impulse
withstand voltage

Equipment
in category

Cat – I
(low impulse
voltage)

1.5 KV

Sensitive electronic equipment –
Eg: TV, Laptop, Electronic Equipments

Cat – II
(normal impulse
voltage)

2.5 KV

Domestic appliances –
Eg : Washing Machine, Fridge,

Cat – III
(high impulse
voltage)

4 KV

Main Distribution Boards

Cat – IV
(very high impulse
voltage)

6 KV

Near the Energy Meter

Let Through Energy

I2t – Let through Energy is available thermal energy resulting from Current Flow during circuit opening. I2t (of circuit breaker) < K2S2 (of cable)

Thermal Classification of Electrical Insulating Materials

Thermal Classification of Electrical Insulating Materials, basis Permissible Temperature Rise above Ambient Temperatuer and Hotspot.

What is Electrical Insulating Materials ?

Nonconducting material that provides electric isolation of two parts at different voltages.
It must have an electrical resistivity and a dielectric strength sufficiently high for the given application.
The secondary requirements relate to thermal and mechanical properties.

Insulation coordination for Switchgear and Assembly as per IEC 60664

Rated Impulse Voltage (Uimp) for Overvoltage category — I, II, III, IV at various nominal Voltage (Ue)

Min Impulse Withstand Voltage for Rated Operatonal Voltage of 230VAC

Categories

Let Through Energy

Thermal Classification of Electrical Insulating Materials

What is Electrical Insulating Materials ?

Motor Contribution in Short Circuit Fault

Effects of Solar Radiation – Solar Gain on outdoor Assembly

When can Arc Flash occur ?

7 Evaluation criteria and Arcing Class for the Internal Arc test of ASSEMBLY as per IEC 61641

What is Arc Blast ?

Properties and Treatment of Ferrous metallic sheets

Insulation coordination for Switchgear and Assembly as per IEC 60664

Rated Impulse Voltage (Uimp) for Overvoltage category — I, II, III, IV at various nominal Voltage (Ue)

Min Impulse Withstand Voltage for Rated Operatonal Voltage of 230VAC

Categories

Tags