patrox2000
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- Location
- Baltimore, MD
what is the difference between sub-feed and feed through panels? thanks.
sub-feed & feed through
- Thread starter patrox2000
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- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
About $100 retail. 
Welcome to the forum.
A feed-through has the incoming power connected to the bus bars, and the conductors going to the downstream panel are also connected to the bus bars. In a sub-feed panel, one of its breakers will be used to provide the connections to the downstream panel. The use of that breaker is the difference in the two types. In both cases, the bus bars of the first panel carry all the current of the first panel, plus all the current of the downstream panel.
There is a third type, called a "double lug." The point at which the incoming conductors connect to the first panel has two sets of lugs. One to connect the incoming conductors, the other to connect a set of conductors going to the downstream panel. Here, the bus bars of the first panel do not see the current from the second panel.
Welcome to the forum.A feed-through has the incoming power connected to the bus bars, and the conductors going to the downstream panel are also connected to the bus bars. In a sub-feed panel, one of its breakers will be used to provide the connections to the downstream panel. The use of that breaker is the difference in the two types. In both cases, the bus bars of the first panel carry all the current of the first panel, plus all the current of the downstream panel.
There is a third type, called a "double lug." The point at which the incoming conductors connect to the first panel has two sets of lugs. One to connect the incoming conductors, the other to connect a set of conductors going to the downstream panel. Here, the bus bars of the first panel do not see the current from the second panel.
DRGREG
Member
Sub feed is connected to OCP, feed thru is connected to the mains.
patrox2000
Member
- Location
- Baltimore, MD
thanks for the explanation.
thanks for the explanation.
Thank you very much.
thanks for the explanation.
Thank you very much.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Sub-feed and thru-feed do not have single universally accepted meanings. And the meanings can change slightly when discussing sub-feed lugs versus sub-feed breakers and main lug only panels versus main breaker panels.
For example, this is the explanation from the squared/com FAQ's:
"Sub feed lugs are for Main Lug Only panels and are located at the main end of the panel.
Thru Feed Lugs are typically for Main Breaker panels and are located at the end of the panel opposite the main breaker."
I have always liked the diagrams in this old Square D publication PN107
http://ecatalog.squared.com/pubs/El...ppliance Branch-Circuit Panelboards/PN107.pdf
For example, this is the explanation from the squared/com FAQ's:
"Sub feed lugs are for Main Lug Only panels and are located at the main end of the panel.
Thru Feed Lugs are typically for Main Breaker panels and are located at the end of the panel opposite the main breaker."
I have always liked the diagrams in this old Square D publication PN107
http://ecatalog.squared.com/pubs/El...ppliance Branch-Circuit Panelboards/PN107.pdf
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