Test Pin with UL 1310 Figure 16.1

16 Accessibility of Live Parts
16.1 General
16.1.1 A live part that poses a risk of electric shock shall be located or enclosed so that the risk of contact is reduced.
16.1.2 The input impedance of the voltmeter used to measure voltage in accordance with the requirements of 16.2.1 and 16.3.1 is to be a minimum of one megohm. The input impedance of a meter with more than one megohm input impedance can be lowered by using shunt impedance.
16.1.3 A guard, baffle, or cover that can be removed without using a tool is to be removed when determining if a live part is accessible to the user. A live part that can be contacted by the test pin, articulate probe, or accessibility probe illustrated in Figure
16.1, Figure 16.2, or Figure 16.4 is considered to be accessible.

SMT S2962_AL

Exception: For direct plug-in units provided with removable blades for the input connectors, accessibility of live parts shall also be determined on the plug module while removed from the direct plug-in unit, even if tools are required for removal.

16.2Live parts other than exposed wiring terminals
16.2.1 The test pin and articulate probe illustrated in Figure 16.1 and Figure 16.2, respectively, when applied as indicated in 16.2.2, shall not contact:
a) A primary circuit; or
b) Any live part with a voltage greater than that specified in 16.2.2 with respect to ground or any other live part simultaneously accessible to the test pin or articulate probe.
16.2.2 The maximum voltages which may be accessible in accordance with16.2.1(a) are:
a) 42.4 V peak for sinusoidal or nonsinusoidal AC;
b) 60V for continuous DC, or 60 V peak for interrupted DC outside the range of 10-200Hz;
c) 24.8 V peak for DC interrupted at a rate of 10-200Hz; and
d) As indicated in Figure 16.3 for combinations of AC and DC.
For the purpose of this requirement, initial transients lasting less than 200 milliseconds may be ignored. Since short term peak voltage is of interest during tests involving a fault, voltages are to be monitored by using a storage oscilloscope for the first two seconds after any fault is introduced.

Test Pin with UL 1310 Figure 16.1

Exception No. 1:The voltage may be exceeded if the current between the parts does not exceed 0.5 mA when measured in accordance with Leakage Current Test, Section 26.
Exception No. 2:The maximum voltage in 16.2.2 (b) and (d) may be exceeded provided:
a) The power supply is in a no-load or “hiccup” condition;
b) The power supply includes a load detection circuit that cycles the output “On” and “Off” resulting in a repetitive waveform;
c) The peak value decays to an average voltage prior to the next “On” state that is less than 60 V;
d) The voltage at the “On” state does not exceed 120 Vpeak; and
e) The voltage (RMS) of the repetitive waveform is less than 60 V.