Defined IP ratings for different type of environment

Type of assemblies / Type of environment                                         Standards and sub-clause                                            Minimum degree of protection

Switchgear and control gear assembly: enclosed switchboard     IEC 60439-1 sub-clause 2.3.3 Not defined

Assemblies for outdoor installation                                                         IEC 60439-1 sub-clause 7.2.1.3                                    IPX3

Assemblies with protection by total insulation                                    IEC 60439-1 sub-clause 7.4.3.2.2                                IP2XC

Installations in normal environments

Live parts which are not be touched intentionally                             IEC 60364-4 sub-clause 412.2.1                   IPXXB (IP2X)

Live parts which are readily accessible (horizontal top)                   IEC 60364-4 sub-clause 412.2.2                                   IPXXD (IP4X)

Installations in locations containing a bath tube or shower basin

Zones 1 and 2                                                                                                    IEC 60364-7 sub-clause 701.512.2                              IPX4

Zone 3                                                                                                                  IEC 60364-7 sub-clause 701.512.2                              IPX1

Zones 1–2–3 public baths where water jets are used for

cleaning purposes                                                                                           IEC 60364-7 sub-clause 701.512.2                              IPX5

Installations for swimming-pools

Zone 0                                                                                                                  IEC 60364-7 sub-clause 702.512.2                              IPX8

Zone 1                                                                                                                  IEC 60364-7 sub-clause 702.512.2                              IPX5

Zone 2 for indoor locations                                                                          IEC 60364-7 sub-clause 702.512.2                              IPX2

Zone 2 for outdoor location                                                                         IEC 60364-7 sub-clause 702.512.2                              IPX4

Zone 2 where water jets are used for cleaning purposes               IEC 60364-7 sub-clause 702.512.2                              IPX5

Installations for rooms and cabins containing sauna heaters         IEC 60364-7 sub-clause 703.512.2                              IP24

Assemblies for construction sites (ACS)                                                                 IEC 60439-4 sub-clause 7.2.1.1                                    IP44

Heat Dissipation in Electrical Enclosures

The accumulation of heat in an

enclosure is potentially damaging

to electrical and electronic devices.

Overheating can shorten the life

expectancy of costly electrical

components or lead to catastrophic

failure. It is therefore important that

system designers are aware of the

temperature implications of their

designs prior to implementation.

 

Enclosure Temperature Rise The

temperature rise illustrated by the curve in the

graph below is the temperature difference

between the air inside the enclosure and the

air outside the enclosure (or ambient air

temperature).This value is described in the

graph as a function of input power in watts per

square foot. In order to predict the

temperature inside the enclosure, the

temperature rise indicated in the graph must

be added to the ambient temperature where

the enclosure is located.

The enclosure temperature rise is not

dependent on the ambient temperature; rather,

the temperature rise for a given enclosure and

heat input are constant. For example, if the

graph indicates a temperature rise of 30° F, the

interior of the enclosure will be 30° F warmer

than the temperature in the surrounding area.

If the temperature in the surrounding area

reaches a maximum of 100° F then the

enclosure interior will reach a maximum

of 130° F.

Since temperatures in an environment often

vary widely, temperatures within enclosures

will also vary. In general, industrial

environments are warmer in the summer than

in the winter.Therefore, when calculating the

warmest enclosure temperature, use the

maximum ambient temperature that is attained

in a given environment.

 

Enclosure Heat Input For any temperature

rise calculation, the heat generated within the

enclosure must be known.This information

can be obtained from the supplier of the

components mounted in the enclosure. Heat

input values are usually given in watts, but may

also appear in BTU/hour. BTU/hour can be

converted to watts by dividing the value by

3.414 (for example, 341 BTU/hour = 100 watts).

It is not possible to approximate the heat input

for a particular application based on enclosure

size. Heat input varies from application to

application for all enclosure sizes.The system

designer must obtain estimates of heat

input from the information that is available.

Safety factors should be considered if any

uncertainty exists.

 

Enclosure Surface Area The physical size

of the enclosure will be the primary factor in

determining its ability to dissipate heat.

The larger the surface area of the enclosure,

the lower the temperature rise due to the heat

generated within it.

To determine the surface area of an enclosure

in square feet, use the following equation:

Surface Area = 2[(A x B) + (A x C) + (B x C)]÷

144 where the enclosure size is AxBxC

This equation includes all six surfaces of the

enclosure. If any surface is not available for

transferring heat (for example, an enclosure

surface mounted against a wall), it should not

be included in the calculation. It is also

noteworthy that enclosure volume cannot be

used in place of surface area

 

Other Enclosure Materials The graph

below applies to enclosures that are gasketed,

non-ventilated, and constructed of painted

steel. Paint color has little effect on enclosure

temperature rise, except when exposed to sun

(see “Outdoor Applications”). Higher

temperature rises can be expected with

aluminum and stainless steel enclosures due to

the poor radiant heat transfer effects of their

metallic finishes.To find the temperature rise of

these enclosures, multiply the results found in

the graph by 1.5. Non-metallic enclosures have

similar heat transfer characteristics to those

constructed of painted steel, so the graph can

be used directly despite the difference in

material.

What is IP69K?

What is IP69K?

 

The IP69K rating is for applications where high

pressure and high temperature washdown is used to

sanitize equipment.

The IP69K test specification was initially developed

for road vehicles, especially those that need regular

intensive cleaning (dump trucks, cement mixers, etc),

but has been widely adopted in the Food & Beverage

industries as a test of products to withstand sanitary

washdown.

 

What does IP69K mean?

 

In the IEC 60529 rating system, IP6 refers to the product’s ability to resist

ingress of dust. The 69K refers to the product’s ability to resist ingress of

high temperature (Steam) / high pressure water.

 

How is the product tested?*

 

• Products rated to IP69K must be able to withstand high-pressure and

steam cleaning.

• The test specifies a spray nozzle that is fed with 80 °C water at 80–100

bar (~1160-1450) and a flow rate of 14–16 L/min.

• The nozzle is held 10–15 cm from the tested device at angles of 0°, 30°,

60° and 90° for 30 seconds each.

• The test device sits on a turntable that rotates once every 12 seconds

Internal Arc Fault Test

Guide for the Design and Production of LV Power Factor Correction Cubicles

 

DOWNLOAD :

 

http://www2.schneider-electric.com/documents/panelbuilders/en/shared/application-solutions/LV_PFC_PB_Guide.pdf

Dead-front panels

Dead front is defined in Article 100 of the NEC as being “without live parts exposed to a person on the operating side of the equipment.” Section 408.38 requires that panel boards be mounted in cabinets, cutout boxes or enclosures designed for the purpose and shall be dead front. The term “dead front” is used in other places in the NEC, but basically, the NEC requires distribution panels, panel boards (load centers), switchboards (stage and theater) be constructed so that switches, circuit breakers and other electrical components can be operated without the user being exposed to live parts.

Circuit breaker accessories - Service releases

Shunt opening release

 

This allows circuit-breaker opening by

means of an electric command. Release

operation is guaranteed for a voltage

between 70% and 110% of the rated

power supply voltage Un, both in AC and

in DC. It is always fitted with an auxiliary

limit contact.

 

Under voltage release

 

This opens the circuit-breaker due to a

power supply failure to the release, or

voltage drops to minimum values of 0.7

x Un with a trip range from 0.7 to 0.35 x Un.

After tripping, the circuit-breaker can be

closed again, starting with a voltage

higher than 0.85 x Un. With the undervoltage

release de-energised, neither

circuit-breaker nor main contact closure

is possible.

 

Time-delayed undervoltage release

 

The undervoltage release can be combined

with an external electronic power

supply time-delay device, which allows

circuit-breaker opening to be delayed in

the case of a power cut to the release

itself, according to fixed time-delays of

0.5-1-2-3 [s], so as to avoid unwarranted

trips caused by temporary malfunctions.

It is available for the SACE S3, S4, S5,

S6, and S7 circuit-breakers with power

supply voltages at 110-220 V (50-60 Hz)

only coupled with an undervoltage release

at 310 V DC.

 

Shunt closing release

 

This allows circuit-breaker closure by

means of an electric command. Operation

of the release is guaranteed for a

voltage between 80% and 110% of the

rated power supply voltage Un, both in

AC and in DC.

 

ABB SASE

Information included in the design verification

The design verification serves to document compliance with the specifications

of this standard. It is comprised of 13 individual verifications.

For selected individual verifications, additional sub-verifications in subcategories

may be required. If selected verifications are not required

due to the application, the respective verification should, as a minimum

requirement, state that verification on the basis of the standard is not

required in this instance.

 

1.       Strength of materials

Verification of material strength is divided into seven sub-points. If

an empty enclosure pursuant to IEC 62208 was used and no modifications

have been made which could influence the functioning

of the enclosure, no further strength testing of the materials for this

enclosure is required. Compliance with standard IEC 62208 should

then be confirmed in the design verification. However, verification

of the resistance of the insulating materials to abnormal heat and

fire for the components used in the busbar system and other insulating

materials should additionally be provided.

a. Resistance to corrosion

Resistance to corrosion can only be verified by testing. For resistance

to corrosion, the verification should stipulate the "testing"

method, the degree of severity and the test report number.

 

2.        Properties of insulating materials – Thermal stability of

Enclosures

 

This evidence is only required for enclosures made from insulating

materials, or parts made from insulating materials mounted on the

outside of the enclosure, and which are relevant to the protection

category. Verification should state that the test was passed at a

temperature of 70 °C, for a duration of 168 h, and with a recovery

time of 96 h, and should also include the method and the test

report number/report number.

 

3.        Properties of insulating materials – Resistance to abnormal

heat and fire due to internal electric effects

 

These properties should be verified using the "testing" method on

the material used, or using the "assessment" method with the data

sheets for the basic plastic material. Verification should state that

the properties of the insulating materials meet the requirements of

the glow-wire test depending on the three intended applications:

 960 °C for parts necessary to retain current-carrying parts

in position

 850 °C for enclosures intended for mounting in hollow walls

 650 °C for all other parts

The design verification should include the test method, the result of

the test, and the test report or report number.

 

4.        Resistance to ultra-violet (UV) radiation

 

Resistance to UV radiation only applies to enclosures and external

parts of switchgear and controlgear assemblies for outdoor installation.

Verification may be provided by testing or by assessing the

data from the original material manufacturer. The design verification

should include the test method, the result of the test method,

and the test report or report number.

 

5.        Lifting

 

Verification for lifting can only be provided by testing. Verification

should state that the test was passed, indicating the maximum

number of sections that can be lifted and the maximum weight,

together with the test report number.

 

6.        Mechanical impact

 

The impact resistance of a switchgear and controlgear assembly is

verified by testing. The design verification should state the method,

the tested IK protection category, and the corresponding test

report number.

 

7.        Marking

 

There is no requirement to test markings made by moulding, pressing,

engraving or similar, as well as labels with a laminated plastic

surface. In such cases, it is sufficient to state the chosen technique

in the design verification. For all other types of marking, testing is

mandatory. The test outcome should be documented, stating the

test report number.

 

RITTAL (Standard compliant switchgear & controlgear production)

Calculation of the temperature rises in compliance with the Std. IEC 60890

Calculation of the powers generated by the different

components and dissipated inside the assembly

 

The calculation of the power losses reported in the

configurations shown is carried out by taking into account

the effective powers dissipated by the different

components.

 

Circuit-breakers

Given the power losses at the rated current (In) shown in

the following tables and the current which actually flows

through the circuit-breakers (Ib), it is possible to calculate

the effective power losses of the equipment:

 

 

The values thus obtained must be increasde by a factor

depending on the circuit-breaker type.

This coefficient is used to take into account the connections

which carry current to the circuit-breakers

Open-type and enclosed assemblies

According to the constructional typology the Standard

IEC 61439-1 distinguishes between open-type and enclosed

assemblies.

 

- Enclosed assembly

 

An assembly is enclosed when there are protected

panels on all its sides so as to provide a degree of

protection against direct contact not lower than IPXXB

(see Chapter 4). Assemblies intended to be installed

in common environments shall be of enclosed type

 

- Open-type assembly

 

An assembly, with or without front covering, in which

the live parts of the electrical equipment are accessible.

Such assemblies can be used only in places

where skilled persons have access for their use.

Rated electrical characteristics of an assembly

Rated voltage (Un)

Highest nominal value of the a.c. (r.m.s) or d.c. voltage,

declared by the assembly manufacturer, to which the

main circuit(s) of the assembly is (are) designed to be

connected. In three-phase circuits, it is the voltage

between phases.

Rated operational voltage (Ue)

it is the rated voltage of a circuit of an assembly which

combined with the rated current of this circuit determines

its application. For three-phase circuits such voltage corresponds

to the voltage between phases.

In an assembly there are usually a main circuit with its

own rated voltage and one or more auxiliary circuits with

their own rated voltages.

The manufacturer of the assembly shall state the limits of

voltage necessary for correct functioning of the circuits

inside the assembly.

 

Rated insulation voltage (Ui)

it is the voltage value of a circuit of an assembly to which test voltages

(power frequency withstand voltage) andthe creepage distances are referred.

The rated voltage of each circuit shall not exceed its

rated insulation voltage.

Rated impulse withstand voltage (Uimp)

it is the peak value of an impulse voltage which the circuit

of an assembly is capable of withstanding under specified

conditions and to which the values of clearances

are referred. It shall be equal to or higher than the values

of the transient overvoltages occurring in the system in

which the assembly is inserted.

Rated current of the assembly (InA)

It is a new characteristic introduced by the Std. IEC

61439 and normally indicates the maximum incoming

permanent and allowable load current or the maximum

current which an assembly is capable of withstanding.

The rated current shall be withstood in any case, provided

that the temperature-rise limits stated by the Standard

are complied with.

Rated current of a circuit (InC)

It is the current value to be carried out by a circuit without

the temperature-rise of the various parts of the assembly

exceeding the limits specified according to the testing

conditions of Clause 7.

Rated short-time current (Icw)

it is the r.m.s. value of the current for the short-circuit test

for 1 s time; such value, declared by the manufacturer

does not imply the opening of the protective device

and is the value which the assembly can carry without

damage under specified conditions, defined in terms of

current and time. Different Icw values can be assigned to

an assembly for different times (e.g. 0.2 s; 3 s). Manufacturer,

can withstand satisfactorily for the operating

time of the device under the specified test conditions.

Rated diversity factor (RDF)

it is the per unit value of the rated current, assigned by

the assembly manufacturer, to which outgoing circuits

of an assembly can be continuously and simultaneously

loaded taking into account the mutual thermal influences.

The rated diversity factor can be stated:

- for groups of circuits;

- for the whole assembly.

The rated diversity factor is:

The rated diversity factor multiplied by the rated current

of the circuits (In) shall be equal to or higher than the

assumed loading of the outgoing circuits (Ib).

The rated diversity factor is applicable to the outgoing

circuits of the assembly and demonstrates that multiple

functional units can be partially loaded.

When the manufacturer states a rated diversity factor,

this factor shall be used for the temperature-rise test,

otherwise reference shall be made to the values recommended

by the Standard 61439-1 in Annex E.

Rated frequency

value of frequency to which the operating conditions are

referred. If the circuits of an assembly are designed for

different values of frequency, the rated frequency of each

circuit shall be given.

-ABB technical application papers

 

 

Design verification of the new standard IEC 61439