a single pole switch has three cables coming in all netrals are connected and have a cap cover. black are connected with a splice line going to bottom of switch.... other black from top of switch... when i place my voltmeter lead on top of single pole switch ARCS and does not blow fuse? have verified the feed or power coming in but lights on wall are dim??
opposite wall has switch that is for outdoor lights..... its a simgle pole switch when turned off is gives power to above??? any ideas

 

Text is hard to follow. Can you make a wiring diagram of the circuits discussed?

 

You'll have to explain your switch problems in a bit more detail. The wall lights are dimmer than expected when on? And the outdoor lights??

The voltmeter shouldn't arc/spark. Voltmeters have very high resistance, so very little current flows through, thus very little spark (if any) when testing. What kind of voltmeter are you using and where's the second probe?

Is this the only dim light in the house? Are there others?

If you want to check the voltage, you'll need to test it between the hot at the bottom of the switch (or top if the switch is on) and the neutral (or ground). You should see 120v.

 

my apologies, it is hard to explain, switch wall box has 3 cables coming in 14/2 white NMD cable, all white neutrals are pigtailed together.
two blacks are pigtailed with a splice line that goes to bottom screw of S/P switch, the remaining black wire is from top of SP screw. when i touch the top screw with my voltmeter set to AC their is an arc, the other lead is in my hand,
wall lights are dim ( not full lumination)

 

So, your volt meter is reading AC voltage with only one probe touching the switch? Is this a digital or analog (meter with a needle) meter?

Do the light and switches work?

 

Undo the common or black (power) from the cap cover, remove splice. Determine which lead is hot from the common wire. Then connect that to the switch on the one side and the load or light to the other side. Does the light illuminate to full brightness?

 

Use your voltmeter and touch one probe to the bottom (hot) screw on the switch, and the second probe to the ground wire in the box or the neutral wire. What voltage does it read?

The meter attached with only one probe isn't doing anything. I'm curious how large the spark is... but in the end it doesn't really matter.

 

Make sure the meter is set to ACV - volts...... not AC amps.

 

The place that arced might be a loose connection. (Does it arc when you touch it with a non-metallic object such as a wood stick or a twig?)

If a connection starts to arc because it is working loose then it will not trip a breaker at that time while lights powered by that circuit can dim down.