Paging Electricians!

[octopus5alive]

Ok, I'm needing to put a subpanel right above a full main panel in my neighbor's house.

The only circuit the sub is running is a couple of lights, one a halogen motion sensor light in the back yard and a sodium nightlight in the driveway, both wired with 14/2 and meet in a junction box with the original garage light wiring, 4 conductor aluminum wiring.

I used the red conductor, origionally for a 3 way circuit as my lead from the switch box to my two 14's leading to lights. Hit the switch and trip the 15 amp kitchen breaker the circuit is on.

So I'm thinking run a subpanel and tie in to the two light circuit, run through 20 amp breaker, use it as the switch, screw the aluminum all togather.

Can't tap out from the main lugs, right?

So do I ****** a spot on the bus and put in a 40amp and run the lead to the box along with the now displaced twenty amp lead to God knows where and run two twenty amp breakers?

Thanks for reading!!

 

[thefairlaneman]

Ok, I'm needing to put a subpanel right above a full main panel in my neighbor's house.

The only circuit the sub is running is a couple of lights, one a halogen motion sensor light in the back yard and a sodium nightlight in the driveway, both wired with 14/2 and meet in a junction box with the original garage light wiring, 4 conductor aluminum wiring.

I used the red conductor, origionally for a 3 way circuit as my lead from the switch box to my two 14's leading to lights. Hit the switch and trip the 15 amp kitchen breaker the circuit is on.

So I'm thinking run a subpanel and tie in to the two light circuit, run through 20 amp breaker, use it as the switch, screw the aluminum all togather.

Can't tap out from the main lugs, right?

So do I ****** a spot on the bus and put in a 40amp and run the lead to the box along with the now displaced twenty amp lead to God knows where and run two twenty amp breakers?

Thanks for reading!!

I connected directly to the main supply breaker that feeds my house panel ,then I put in that circuit a safety pull out fuse box and then ran the power from it to my sub panel in my shop. Did it 7 years ago and no problem, BUT BE SURE YOU REMOVE THE METER FIRST TO RENDER THE COMPLETE SYSTEM DEAD BEFORE YOU MAKE THE CONNECTIONS,,,,,,,,,,,

 

[octopus5alive]

I connected directly to the main supply breaker that feeds my house panel ,then I put in that circuit a safety pull out fuse box and then ran the power from it to my sub panel in my shop. Did it 7 years ago and no problem, BUT BE SURE YOU REMOVE THE METER FIRST TO RENDER THE COMPLETE SYSTEM DEAD BEFORE YOU MAKE THE CONNECTIONS,,,,,,,,,,,

so on the breaker, it was on the south side of the meter lugs...ie on the buss side?

 

[Charles (in GA)]

Aluminum wire, I would not touch that with the proverbial ten foot pole. I had a house with aluminum wire and have had other dealings with it before, and for branch circuits its no longer allowed by code and in any case requires special wirenuts, and all connections must be marked AL/CU. You also need to use anti-corrosive past on all connections.

What TheFairlaneMan is suggesting leaves you with smallish wires feeding off your main breaker (large in capacity) thus not protecting the small wires, before the fused pullout he mentioned.

Why not buy one or two tandem or double breakers, two breakers in the space of one normal one and replace an existing one or two with them. I'm betting this is not a 40 space panel and so if it is full, it still probably doesn't have 40 breakers in it. Safer, cheaper and less hassle. It sounds like you have a mess going, I would not want to be associated with.

Charles

 

[Vermaraj]

If your going to run a sub-panel you might as well size the wire and breaker according to capacity rather than you immediate need. The increased cost in wire and breaker is less than $100.

Tapping off your main breaker, unless its a disconnect with a distribution block, is not a good idea for many reasons. Not the least of which is your undersized wires feeding the sub-panel potentially pulling 125% of the main breaker amperage rating. In case of a short you will likely start an electrical fire in your main panel.

 

[thefairlaneman]

If your going to run a sub-panel you might as well size the wire and breaker according to capacity rather than you immediate need. The increased cost in wire and breaker is less than $100.

Tapping off your main breaker, unless its a disconnect with a distribution block, is not a good idea for many reasons. Not the least of which is your undersized wires feeding the sub-panel potentially pulling 125% of the main breaker amperage rating. In case of a short you will likely start an electrical fire in your main panel.

The wires I used to supply my fuse pull out coming from the main breaker are large enough to carry double the load Im using in my shop. My idea was that if these wires get hot they will surely throw the main braker. Is this not so? Im not a pro electricin.

 

[Vermaraj]

The wires I used to supply my fuse pull out coming from the main breaker are large enough to carry double the load Im using in my shop. My idea was that if these wires get hot they will surely throw the main braker. Is this not so? Im not a pro electricin.

Its not clear to me where your tapping into. What I was trying to describe is the wires coming from the meter landing on the main breaker. The main breaker then feeds the bus bars directly or using a short length of cable.

If your tapping off the bus bar side of the main breaker then you need wire that is sized at the full load rating of the breaker + the usual spike current usually ~25% (assuming that the main breaker is a delay trip). During a short circuit those wires can pull the full load required to trip the main breaker. If they are undersized they can cause a fire.

If your tapping off the meter side of the main breaker then you need to be in compliances with distribution requirements, because now you can pull as much power as the street transformer will provide. To do so you would land the wires from the meter into a fused disconnect and then run equal sized feeders to each panel (which also must have equal capacities). This may or may not pass code in your locality. Now your getting into industrial wiring techniques which differ from residential technique. Using a breaker fed sub-panel is cheaper and easier than this method.