Split bus panel

[Tom Rees]

Hi, hope everyone had a great weekend. I ran into this panel the other day and recommended it be replaced. I have a question on just how this kind of split bus panel was intended to be used. The main lugs go only to the bottom bus bar and then a double tap at the lugs goes to a breaker on the upper bus. Could someone briefly explain this to me. Thanks. Sorry about the quality of the picture.

[Garry Blankenship]

Neither electricity not the code cares whether the six or fewer disconnects are on the top or the bottom of a split buss panel. First; cannot tell which portion of the panel is fed hot and which is fed through a breaker. Second; double taps, ( more that one conductor in the same termination ) are illegal, unless that termination is listed / approved for more than one conductor. Third; the circuit breaker that supplies the sub-fed portion of the panel must be secured to the panel. Hard to go any further w/ the limited detail.

[Tom Rees]

The bottom is fed hot the top is fed thru breaker. I know about all the things wrong with this first it using "Stab-Lok" breakers. I just don't get the logic behind this type of split bus panel or any split bus panel. Here's another picture.

[Garry Blankenship]

The bottom is fed hot the top is fed thru breaker. I know about all the things wrong with this first it using "Stab-Lok" breakers. I just don't get the logic behind this type of split bus panel or any split bus panel. Here's another picture.

The logic behind split buss panels is money. The 60 amps and down circuit breaker frame size is the least expensive. By taking advantage of the code allowing up to six main disconnects, money could be saved by splitting up the buss. The main section supplys the major loads, ( like the range, water htr., dryer, elec heat sometimes or maybe a sub panel ). One of the allowable six main disconnects is dedicated to supplying the separate or "split" off buss in the same panel which in turn powers the smaller load branch circuits in a typical home, ( like lighting & receptacle circuits ). The "split" off buss in a split buss panel is really a sub-panel - - - it's just in the same enclosure as the main disconnect section. The largest circuit breaker to be found in a split buss panel might be 60 amps, saving the cost of larger frame size circuit breakers like a 200 amp breaker. Admittedly some manufacturers go as high as 125 amps in the same frame size, but they still make you pay a lot more for them. Other manufacturers will change their frame size at 70 amps then another frame size when you exceed 125 amps. Short version; split buss panels helped avoid the higher cost of bigger circuit breakers.

[Tom Rees]

Thanks Garry. I'm assuming then that the correct way to supply power to the top buss would be from a single pole breaker on the bottom buss to a single pole breaker on the top buss, not from the lugs?