High Voltage Soldering (IPC Standards?)

[kenpeter]

Training today covered IPC standard for soldering high voltage
terminals. However, some of IPC's standard seem at odds with
IPC standards for those same terminals at lower voltage.

For example, a turret:

At low voltages the target for appearance shows to wrap 180
degrees. And 75% or better wetted fillet of solder, with 90 deg
or lower contact angles. The outline of the strands should be
slightly visible in the solder.

But for high voltages, they want a round or egg shaped blob of
solder to completely encapsulate the strands and all possible
sharp edges.

The standard doesn't seem to specify when to use which style.

How many Volts, or how many Volts/mm defines "High Voltage"?
High enough that advantages of smooth blobbery overtakes the
advantages of pretty solder joints?

[kevinkr]

Sharp points initiate arc discharge (electrostatic field is more concentrated at the end of pointy objects and may ionize surrounding air leading to breakdown and an arc) to surrounding points, anything over 1KV should be considered high voltage and possibly lower. (Gut feeling on threshold voltage.)

[gingertube]

Kenpeter.

International Standards (IEC) definitions:

Extra Low Voltage: less than 50 V RMS AC or 120 Volt "Ripple Free" DC

Low Voltage: 50 to 1000 V RMS AC or 120 to 1500 Volt "Ripple Free" DC

High Voltage: greater than 1000V AC RMS or 1500 Volt "Ripple Free" DC

HOWEVER if there is one thing you "Yanks" excell at, it is ignoring International Standards and creating your own.

US Standards define High Voltage as greater than 600V RMS AC or 900V "Ripple Free" DC.

I would think IPC would follow International Standard definitions BUT could be WRONG.

Cheers,
Ian

[nhuwar]

I thought 1kv was only medium voltage.


If memory serves it 1kv to 35kv High voltage is above 35kv.

Smooth surfaces reduce voltage gradients instead of sharp points which increase or concentrate them. And As Kevin said a sharp point will cause corona and or initiate a discharge point.

Nick