2 circuit breakers bridged to one circuit

Reply

  #1  
Old 08-09-08, 04:48 PM
Member
Thread Starter
Join Date: Aug 2008
Posts: 1
Received 0 Votes on 0 Posts
2 circuit breakers bridged to one circuit

I am remodeling our Kitchen and have to make some wiring changes, so started by making an analysis of what loads are on each circuit. Everything is reasonably straight forward, except loads from (2) 15 amp 120v breakers in the panel.

The 15 amp breaker in position 6 controls:

Motion Activated Exterior Floods (1) 2 bulb unit
Regular Exterior Floods (1) 2 bulb unit
Garage Fluorescent Box Lights (2)
Garage Sockets (8) (only a few used at a time, though)
Den Sockets either side of fire place (2) and to left of sliding glass door (1)
All Deck Sockets (5)
Garage Door Opener (plugged into one of the garage sockets)

The 15 amp breaker in position 10 controls:

Master Bed Ceiling Fan and Light
Master Bed Sockets (5)
Master Bath Lights ( 7 Fluorescent bulbs)
Bedroom 1 Fan and Light
Bedroom 1 Outlets (4)
Motion Activated Exterior Floods (2) 2 bulb units.
˝ hp Well Pump Socket (1)

There is a wall switch near the deck (a DIY add on by previous owners), which in the “on” position seems to bridge these two circuits, such that if either circuit is on, then power will flow to both circuits. If this switch is off, then the circuits are isolated. There are two black wires to this switch. Disconnecting the wires and capping them off does not seem to cause anything not to work, and with them disconnected, the circuits are separated and seem ok.

There is no bridging or multiple wires coming out of the breakers in the breaker box.

So, questions:

- Is it Ok to leave it this way, with the two black wires capped in the outlet box, or should I have a qualified electrician come out and check it further?
- Doesn’t (2) 120v circuits joined together make 240v?
- Was there an increased fire/short circuit/electrocution risk from these circuits being bridged this way?

AND unrelated to the above, I am considering a two zone dimmer installation with about 500w per dimmer. I am looking at the Maestro dimmer with companion dimmer. I understand if you have two of these ganged, you have to de-rate, but does the same apply if you have one master, and one companion, ganged? The companion one – is it operating as a “virtual” remote, or is it carrying the 500w current?

Thanks in advance for the help!!


Location - Jacksonville, Florida...
 
Sponsored Links
  #2  
Old 08-09-08, 07:03 PM
Member
Join Date: Jun 2008
Location: Eastern Georgia
Posts: 486
Received 0 Votes on 0 Posts
Call an electrician! There are too many devices on each of those circuits, the need to be split up. As far as bridging breakers 6 and 10 would be on the same leg in the panel so there is no danger of getting 220 volts by doing this, I do not understand the reason it was done that way, have an electrician check it out before adding anything else.
 
  #3  
Old 08-10-08, 01:30 AM
Member
Join Date: Jul 2008
Posts: 47
Received 0 Votes on 0 Posts
I would agrre to call a electrician if nothing else to figure out that switch. It does not make any sense and have a sneaking suspicion this switch was meant to control something. There is no raeson it is like that. When you have 2 circuits that collide with one another it generally will blow both breakers because they are back feeding each other. In your case this isn't the case because of the position of both circuit breakers. They are both on the same phase so you don't have 2 opposing forces. Every other breaker is a different phase in a zig zag pattern in any panel. Because it is on the same phase the breaker will not trip and the 2 circuits basically become one.
 
  #4  
Old 08-11-08, 09:53 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
Originally Posted by reidg View Post
The 15 amp breaker in position 6 controls:
...

The 15 amp breaker in position 10 controls:
...
Both of these circuits have the potential to be pretty overloaded, especially the 1/2HP pump. That should be on a dedicated circuit. The number of receptacles and lights on these circuits is consistent with wiring practices in an older home, but would be considered too much by modern standard. If you're re-doing wiring anyway, it's a good time to update these circuits.

Regardless of what you choose to do with the rest of these circuits, I would strongly urge you to install or have a dedicated circuit installed for the pump. A 1/2 HP pump uses 10A just by itself.



There is a wall switch near the deck (a DIY add on by previous owners), which in the “on” position seems to bridge these two circuits, such that if either circuit is on, then power will flow to both circuits.
This is usually the result of someone screwing up a three-way light switch installation. If you're handy with troubleshooting skills, you can probably find the problem. If not, an electrician should be able to sort it out.

Is it Ok to leave it this way, with the two black wires capped in the outlet box, or should I have a qualified electrician come out and check it further?
It's okay in the sense that it's almost certainly safer. There still could be an underlying problem however like interconnected neutrals that may be worth sorting out.

Doesn’t (2) 120v circuits joined together make 240v?
Only if they're from opposite legs of the panel. If they're from the same leg of the panel you essentially get one 30A 120V circuit which has the potential of causing overloads on any shared segments of #14 wire which is only rated for 15A.

Was there an increased fire/short circuit/electrocution risk from these circuits being bridged this way?
Yes. In addition to the possibility of a wire overload, it is an electrocution hazard for anyone who is working on the circuit when the backfed switch is accidentally thrown and shocks him.

does the same apply if you have one master, and one companion, ganged? The companion one – is it operating as a “virtual” remote, or is it carrying the 500w current?
The companion units ("accessory dimmers") do not require any derating. They are just receivers which transmit a control signal to the master unit.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: