over current protection

Status
Not open for further replies.

markdeuce

Member
Question- is a overcurrent devise or service disconnect required in this application. subdivision entrance exterior panel for lighting-
SE cable comes out of the meter can and into the MLO panel. opening for up to 8 breakers. only breaker installed is for lighting (30amp)
my opinion there in no disconnect, no over current devise, no way to turn panel off unless metter is pulled.

(i have a picture )
 

raider1

Senior Member
Staff member
Location
Logan, Utah
Welcome to the forum.:)

Is the panel listed as suitable for use as service equipment?

The service disconnecting means can consist of up to six circuit breakers that are grouped together.

Check out 230.71 and 230.72.

Chris
 

markdeuce

Member
yes , suitable for use as service equipment.

what about over current devise for service entrance cable, also it states if used as main breaker -requires hold-down kit.
this has no main breaker, bus bars are open (once panel cover is pulled) .
i see that the only breaker serves the curcuit being used.
if you needed to service panel or bus bar there is no main, and up to 6 throws of the hand- but doesnt it require at least one-main?
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
yes , suitable for use as service equipment.

what about over current devise for service entrance cable, also it states if used as main breaker -requires hold-down kit.
this has no main breaker, bus bars are open (once panel cover is pulled) .
i see that the only breaker serves the curcuit being used.
if you needed to service panel or bus bar there is no main, and up to 6 throws of the hand- but doesnt it require at least one-main?

The service entrance conductor is protected by the 30 amp if you will. Every service the se conductors are either protected by a main or up to 6 discos. Chris quoted that article number. No main is needed.

Also no hold down is needed unless that breaker is the protection for the entire panel. The breaker would have to be backfed in order to require a hold down.
408.36(D) Back-Fed Devices. Plug-in-type overcurrent protection devices or plug-in type main lug assemblies that are backfed and used to terminate field-installed ungrounded supply conductors shall be secured in place by an additional fastener that requires other than a pull to release the device from the mounting means on the panel.
 

WinZip

Senior Member
All I can say I have never set up a service without a main , now sub service is different story , sub service beside a main panel needs no main , sub panel in out building no more than 6 breakers no main after 6 it needs main breaker.

Reminds me of the old split bus panels back in the 70-80's
 

iwire

Moderator
Staff member
Location
Massachusetts
All I can say I have never set up a service without a main ,

Very common set up for large services, the service condutors run to a main lug only panel or switch board. From there you can have 6 (sometimes more) service disconnects supplying 'sub panels' or large equipment.

This often done to avoid having to comply with the requirement for ground fault protection of large services or the cost of a single large breaker / switch etc.
 

markdeuce

Member
heres a question, if panel is rated at 125amps max without a max diconnect to protect the panel or without a back fed main breaker- is it possible to over load the panel from the power company side?
2nd- i understand where everyone is coming from on the 1/6 throws but i cant keep thinking this one does not have any disconnect- my thinking is that the 20or 30 amp is just protection that curcuit. (i am trying to let this rest) i have asked my local outstanding electricans and we are still 50-50 on this.
 

Volta

Senior Member
Location
Columbus, Ohio
heres a question, if panel is rated at 125amps max without a max diconnect to protect the panel or without a back fed main breaker- is it possible to over load the panel from the power company side?
Not if the load calculations are good ;).
2nd- i understand where everyone is coming from on the 1/6 throws but i cant keep thinking this one does not have any disconnect- my thinking is that the 20or 30 amp is just protection that curcuit. (i am trying to let this rest) i have asked my local outstanding electricans and we are still 50-50 on this.

It is protection for the branch, by design. But in this situation it absolutely protects the service from overload.

But officially, the service conductors (including the busbars) are protected by math. The calculations for each circuit served, along with demand factors that may be allowed, are what protect these wires.

Welcome to the forum!
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
You have to remember that service conductors never have overcurrent protection...they only have overload protection.
 
This is no different than a temporary service. As comented it can hold up to 6 sets of switches with out a main but as soon as someone adds another breaker in, three to five years down the road (not you), then the service would require a main. Now wether they do that or not is a different story.
 
Status
Not open for further replies.
Top