Main Breaker For Temporary Service Pole ?

[jetlag]

Do you have to have a main breaker in a temporary service box if it has no more than 6 - 20 amp breakers that don't exceed the 125 amp box or the # 2 copper S E cable .?

 

[mbednarik]

Using a MLO panel is now prohibited by 2020 NEC. See 230.71B

 

[Dennis Alwon]

Do you have to have a main breaker in a temporary service box if it has no more than 6 - 20 amp breakers that don't exceed the 125 amp box or the # 2 copper S E cable .?

I agree with mbednarik... The 2020 nec requires a main in your situation.

 

[jetlag]

ok thanks , I hope it is ok to back feed a 60 amp breaker on the buss for the main . That will be plenty of power . I was thinking the other way that the breakers would count as the disconnect if you can kill the power with 6 or less switches .

 

[Dennis Alwon]

ok thanks , I hope it is ok to back feed a 60 amp breaker on the buss for the main . That will be plenty of power . I was thinking the other way that the breakers would count as the disconnect if you can kill the power with 6 or less switches .

The reason the ruled changed was because there was no way to work on the panel safely because you can never kill the power to the bussbar.

If you back feed a panel that would work but you would need a hold down kit and you would need to be able to cover the lugs on the breaker so they are not exposed.

 

[jetlag]

I have installed a lot of RV boxes that came with the 50amp R V receptacle and a 20 amp gfci receptacle made into the outside box . There was a 50 a breaker for the RV and a 20 a breaker for the 20 amp receptacle . There was no main disconnect. So, I guess those boxes are not allowed now with the 230.71 B code ?

 

[jetlag]

It is still ok to use a sub panel with out a main disconnect if the feeder to it has a breaker in the main panel isn't it ?

 

[jetlag]

The reason the ruled changed was because there was no way to work on the panel safely because you can never kill the power to the bussbar.

If you back feed a panel that would work but you would need a hold down kit and you would need to be able to cover the lugs on the breaker so they are not exposed.

thanks Kwred . do they have a universal hold down for one inch spaced breakers with a double pole to hold down ? It is a homeline box . Can you buy a cover also or use something else ?

 

[zbang]

I have installed a lot of RV boxes...

Most RV pedestals are installed on feeders, so there's an upstream disconnect & OCPD. (Are any of them suitable for use as service equipment? I don't think I've ever looked.)

 

[readydave8]

It is still ok to use a sub panel with out a main disconnect if the feeder to it has a breaker in the main panel isn't it ?

If separate structure, will need disconnect, often accomplished by using MBP rather than MLP

 

[norcal]

Around here for temp panels, a 100A meter/main is used, common, fairly cheap, & no labor assembling a meter can, load center, & adding a MB, since it's a factory assembly all in a compact package. Would be a problem where they are not common, or PoCo rules disallow them.

 

[Little Bill]

I think there should be exceptions for temp services. Here, we use a temp panel that has either a 50A and 20A breaker, or just a 20A breaker. The panels are MLO. The rule for the requirement is so power to the bus can be turned off if you need to work in there. On a temp panel, you shouldn't need to be working in it. It is just to provide power for construction purposes. You set it up and done.

We are still on the 2017 and it's not required. Inspectors here say they won't require a main on temp panels should we adopt the newer codes.

 

[kwired]

I think there should be exceptions for temp services. Here, we use a temp panel that has either a 50A and 20A breaker, or just a 20A breaker. The panels are MLO. The rule for the requirement is so power to the bus can be turned off if you need to work in there. On a temp panel, you shouldn't need to be working in it. It is just to provide power for construction purposes. You set it up and done.

We are still on the 2017 and it's not required. Inspectors here say they won't require a main on temp panels should we adopt the newer codes.

There should maybe be some sort of exception for an enclosure designed to house a single overcurrent device as well?

I have used a 100 amp plug on as a service disconnect many times in an assembly designed to only house a single overcurrent device.

The newer rule technically would make it so you must have a unit breaker with lugs on both ends, and would need line barriers for the supply side.
I guess I have no problem with requiring line barrier on the line side but still think if it is designed for a single device it would be ok to have energized bus as long as there is no exposed bus when the device is installed. This would not be a device that would be unplugged from the bus often if ever during it's useful lifetime and would require similar safety procedures if you did unplug it as would be required changing the typical main breaker in a load center.

 

[don_resqcapt19]

For installations under the older codes, you have to look at the panel instructions. There are small panels that are marked "suitable for use as service equipment only where a main breaker is installed".

 

[kwired]

For installations under the older codes, you have to look at the panel instructions. There are small panels that are marked "suitable for use as service equipment only where a main breaker is installed".

True. Most "loadcenters" I have seen have such marking on them.

Only panel I can recall using that I know is ok to use as service equipment with main lug only supply is an I-line panel, but there likely is some others.

 

[mbednarik]

True. Most "loadcenters" I have seen have such marking on them.

Only panel I can recall using that I know is ok to use as service equipment with main lug only supply is an I-line panel, but there likely is some others.

Even though the equipment is labeled as such, anything installed under a 2020 NEC still requires a main.

 

[kwired]

Even though the equipment is labeled as such, anything installed under a 2020 NEC still requires a main.

yes

 

[Greentagger]

I think there should be exceptions for temp services. Here, we use a temp panel that has either a 50A and 20A breaker, or just a 20A breaker. The panels are MLO. The rule for the requirement is so power to the bus can be turned off if you need to work in there. On a temp panel, you shouldn't need to be working in it. It is just to provide power for construction purposes. You set it up and done.

We are still on the 2017 and it's not required. Inspectors here say they won't require a main on temp panels should we adopt the newer codes.

🫣

 

[GoldDigger]

For installations under the older codes, you have to look at the panel instructions. There are small panels that are marked "suitable for use as service equipment only where a main breaker is installed".

Which leads to the unfortunate confusion as to whether that means:
"suitable for use [as service equipment only] where a main breaker is installed" or
"suitable for use as service equipment [only where a main breaker is installed]"

I believe it is the second.