Circuit Fails when wires capped but not when light is inline
A Simple Short Circuit
when the porcelain single bulb light is hooked-up the Black and dotted white wire, the light works and break is Not tripped. Also works fine whether switched off/on. When I cap those two wires together, the break trips to off position.

Black wire going to bulb is &quot;hot&quot;
White wire going to bulb is &quot;neutral&quot;

A circuit is panel -&gt; &quot;hot&quot; -&gt; load (e.g., light) -&gt; &quot;neutral&quot; -&gt; panel.
When you cap the two wires together without any load between them, you let ALL the possible electricity flow through. Otherwise known as a &quot;short circuit&quot;. The breaker then trips, as it is designed to do to protect your wiring and prevent your house from burning down.