Safety Specification
General information .
Ericsson Power Modules DC/DC converters and DC/DC regulators
are designed in accordance with safety standards
IEC/EN/UL 60 950,
Safety of Information Technology Equipment.
Isolated DC/DC converters .
It is recommended that a fast blow fuse with a rating
twice the maximum input current per selected product
be used at the input of each DC/DC converter . If an input filter is
used in the circuit the fuse should be placed in front of the input
filter .
In the rare event of a component problem in the input filter or in the
DC/DC converter that imposes a short circuit on the input source,
this fuse will provide the following functions:
• Isolate the faulty DC/DC converter from the input power source
so as not to affect the operation of other parts of the system .
• Protect the distribution wiring from excessive current and power
loss thus preventing hazardous overheating .
The galvanic isolation is verified in an electric strength test . The test
voltage (V
ISO
) between input and output is 1500 Vdc or 2250 Vdc for
60 seconds (refer to product specification) . Leakage current is less
than 1µA at nominal input voltage .
IEC/EN/UL60950 contains requirements to prevent injury or
damage due to the following hazards:
•
•
•
•
•
•
Electrical shock
Energy hazards
Fire
Mechanical and heat hazards
Radiation hazards
Chemical hazards
On-board DC-DC converters are defined as component power
supplies . As components they cannot fully comply with the
provisions of any Safety requirements without “Conditions of
Acceptability” . It is the responsibility of the installer to ensure that
the final product housing these components complies with the
requirements of all applicable Safety standards and Directives for
the final product .
24 V dc systems .
Component power supplies for general use should comply with
the requirements in IEC60950, EN60950 and UL60950 “Safety of
information technology equipment” .
The input voltage to the DC/DC converter is SELV (Safety Extra Low
Voltage) and the output remains SELV under normal and abnormal
operating conditions .
There are other more product related standards, e .g .
IEC61204-7 “Safety standard for power supplies",
IEEE802 .3af “Ethernet LAN/MAN Data terminal equipment
power”, and ETS300132-2 “Power supply interface at the input to
telecommunications equipment; part 2: DC”,
but all of these standards are based on IEC/EN/UL60950 with
regards to safety .
48 and 60 V dc systems .
If the input voltage to Ericsson Power Modules DC/DC converter
is 75 V dc or less, then the output remains SELV (Safety Extra Low
Voltage) under normal and abnormal operating conditions .
Single fault testing in the input power supply circuit should be
performed with the DC/DC converter connected to demonstrate
that the input voltage does not exceed 75 V dc .
If the input power source circuit is a DC power system, the source
may be treated as a TNV2 circuit and testing has demonstrated
compliance with SELV limits and isolation requirements equivalent
to Basic Insulation in accordance with IEC/EN/UL 60 950 .
Ericsson Power Modules DC/DC converters and DC/DC regulators
are UL 60 950 recognized and certified in accordance with EN 60
950 .
The flammability rating for all construction parts of the products
meets UL 94V-0 .
The products should be installed in the end-use equipment, in
accordance with the requirements of the ultimate application .
Normally the output of the DC/DC converter is considered as SELV
(Safety Extra Low Voltage) and the input source must be isolated by
minimum Double or Reinforced Insulation from the primary circuit
(AC mains) in accordance with IEC/EN/UL 60 950 .
Non-isolated DC/DC regulators .
The input voltage to the DC/DC regulator is SELV (Safety Extra Low
Voltage) and the output remains SELV under normal and abnormal
operating conditions .
It is recommended that a slow blow fuse with a rating
twice the maximum input current per selected product
be used at the input of each DC/DC regulator .
PKB 4000 Datasheet
6
EN/LZT 146 033 R9A © Ericsson Power Modules, March 2007
ERICSSON [ ERICSSON ]
