Standards

1

Merlin Gerin Square D Telemecanique

The International & North American standards

MOE - Presentation 8th Oct


The international & american standards Content

presentation of the standards

the test sequences



presentation of the standards• the standard influences• the North American standards• the international standard• standard comparison

generalities on the tests


The international & american standards The standard influences

IEC

IECIECIEC

IEC JIS

CSA

UL

UL

IEC IEC


The international & american standards The North-American standards

general rules

codes NEC (National Electrical Code)publisher : NFPA (National Fire Protection Association)

guides recommandations CEE

"product" standards

ANSI UL NEMA


The international & american standards The international standard

general rules

codes regionals & nationals (Cenelec, VDE, NF,...)

guides national (C 15-100, ...)

"product" standards

IEC

In ternational Electrotechnical Commission : more than 40 country representatives, institutional users, manufacturers


The international & american standards The international standard

IEC # previouspublication #general rules 947-1 without equivalencecircuit breakers 947-2 157-1switches 947-3disconnectorsswitches / disconnectors 408combined-fusescontactors and starters 947-4 158-1 & 292-2switching devices 947-5 337for control circuit

multiple function 947-6 without equivalence connection devices part 1 : automatic transfer connection equipmentaccessories 947-7 without equivalence


The international & american standards Standard comparison

combined test overload + endurance

short-circuit on Z sequence single phase

temperature rise temperature rise temperature rise temperature rise limited at 80° limited at 50°C limited at 50°C (linked to the evolution of technologies)

insulation impulse voltage creepage distance creepage distance

label of quality no UL listed materials id. UL(manufacturer follow-up id. ULstandard)

IEC 947-2 UL 489 ANSI 37-50 (PCB)


The international & american standards Presentation of the standards

conclusion

UL & IEC standards are historically and culturally based on different approaches : there are not to be compared

UL & IEC standards guaranty the same level of safety for the end user

UL & IEC standards have the same level of constraints



presentation of the standards

the test sequences• generalities on the tests• the sequences of the UL 489• the sequences of theANSI C 37-50• the sequences of the IEC 947-2


The international & american standards generalities on the tests

two types of test : type test routine test

general principle applied on type test whatever thestandard : calibration main tests : overload, short-circuit final checks : dielectric, tripping


The international & american standards Test sequence IEC 947-2

I all calibration of releasegeneral dielectric withstand

performance mechanical / electrical enduranceoverload (6 In)dielectric withstandverification temperature risetrip-out (1.45 In)

II all rated service S/C breaking capacity (O-C0-CO) Ics dielectric withstand

verification of temperature risetrip-out (1,45 In)

III A calibration of release (2 Ir pole / pole)and rated ultimate S/C breaking capacity (O-CO)

Icu B dielectric withstandtrip-out (2,5 In)

test type testséq. breaker description


The international & american standards Test sequence IEC 947-2

IV B calibration of release (2 Ir pole / pole) rated short-time withstand current Icw verification of temperature rise (80°C at connections)

S/C breaking capacity max. short time withstand current (Icw)dielectric trip-out (2 In)

combined B calibration of releases (2 Ir pole / pole) rated short-time withstand current Ics rated service S/C breaking capacity (O-CO-CO) Icw dielectric withstand

verification temperature rise (80°C)trip-out (1,45 In)

test type testséq. breaker description


The international & american standards The IEC 947-2 & the breaker categories

the IEC defines 2 categories of circuit breakers

Category A : not specifically designed for discrimination under short circuit conditions

Category B : specifically designed for discrimination under short circuit conditions, with an intentional time delay

category B circuit breakers have an additional characteristic :

short time rating : Icw (in KA associated with time)

Icw values: CB < 2500A, Icw above 12 In or 5KACB > 2500A, Icw above 30KA


The international & american standards The circuit breaker , a multi-function

safety device ruled by IEC947-2

more safety by Short Circuit breaking capacities, that are close to the reallity.

more safety for maintenance operation by the disconnection function

more continuity of service and dependability, by the recongnition of coordination between two breaker


The international & american standards a clarification of the breaking capacity

the Ultimate breaking capacity (Icu) - the characteristic to be taken into account, and compared to the prospective short circuit level (3 phases bolted short circuit) for the design of an installation- Icu (kA) represents the maximum fault that the breaker can clear - Icu test = O - CO sequence

the Service breaking capacity (Ics)- expresses the ability of the device to eliminate safely short circuits with a greater likhood of occuring.- Ics is given as a % of Icu- Ics test = O - CO - CO, plus service conditions after breaking


The international & american standards the disconnection function

the disconnection capacity of a circuit breaker is garanteed by 3 test for a maximum of safety :

- shock wave voltage strength (Uimp = 12.3 kV)- maximum leakage current under 110% Un- mechanical test on the handle

the identification by a specific symbol


The international & american standards the disconnection function

the disconnection capacity of a circuit breaker is garanteed by 3 test for a maximum of safety :

- shock wave voltage strength (Uimp = 12.3 kV)- maximum leakage current under 110% Un- mechanical test on the handle

the identification by a specific symbol "circuit breaker - disconnector"


The international & american standards

discrimination, for a maximum of continuity of serviceonly the breaker just above the fault trips

cascading, for substantial savingsthe breaking capacity of C2 can be less than the prospective Isc, but the above breaker C1 will "help" for any short circuit value between Icu2 and Isc

Co-ordination between circuit breaker

Engineering

Standards