|
|
An
introduction to TTA,
PTTA & DCAs
TTA
is a 'Type Tested Assembly' and
PTTA
is a 'Partially Type
Tested Assembly' as specified in IEC 60439-1-1999-09, DIN EN 60439-1 (DIN VDE
0660 Teil 500), BS-EN60439-1 is Part 1 of the 439-series of standards and is the
main part covering the general requirements for type-tested and partially
type-tested assemblies. Where customer’s requirements cannot be covered by the
former, Mertech offer a
DCA
which is a Design Centre Assembly engineered to the
specific requirement of the IEC-60439-1-1999 standard, without the type tests.
It is a requirement of the manufacturer to
establish, within his ISO 9000 Quality Assurance System, procedures which will
ensure he is fully satisfied the equipment he is providing complies with the
standard and that the equipment is fit for the purpose.
|
Type Tested Assembly
| 
Partially Tested Assembly
| 
Design Centre Assembly |
|
A low-voltage switchgear and controlgear assembly conforming
to an established type or system without deviations likely to
significantly influence the performance, from the typical assembly
verified to be in accordance with this standard.
The following seven laboratory tests have been certified:
1 Temperature rise Limit.
2 Properties.
3 Short circuit
withstand.
4 Protection circuit
efficiency.
5 Clearance and
creapage distance.
6 Mechanical operation.
7 Degree of protection.
Mertech manufactures TTA arrangements up to
3200 Amp busbars. Type Tests provided by KEMA.
|
A low-voltage switchgear or controlgear assembly, containing
both type-tested and non-type-tested arrangements provided that the
latter are derived (e.g. by calculation) from type tested arrangements
which have complied with the relevant tests.
The following laboratory test has been certified:
1 Short Circuit Withstand
The following parameters are extrapolated:
1 Temperature rise
Limit.
2 Properties.
3 Protection circuit
efficiency.
4 Clearance and
creapage distance.
5 Mechanical operation.
6 Degree of protection.
Mertech manufactures PTTA switchboards utilising its Type Tested
busbar system or extrapolations of it and extrapolated designs from
its Type Test Assembly for all other parameters. Type Test
provided by ASTA.
|
A low-voltage switchgear or controlgear assembly, containing
non-type-tested arrangements derived by good engineering practice from
type tested arrangements which have complied with the relevant tests.
This DCA falls under the same category as PTTAs but cannot claim full
compliance.
The following parameters are extrapolated:
1 Temperature rise Limit.
2 Properties.
3 Short
circuit withstand.
4 Protection
circuit efficiency.
5 Clearance and
creapage distance.
6 Mechanical
operation.
7 Degree of
protection.
Mertech manufactures DCA switchboards utilising
extrapolations from its ASTA tested busbar system and extrapolated
designs from its Type Tested Assembly for all other parameters.
No Type Tests
offered.
|
