Generator backup

[jog]

Working on a mobile home,they want a generator back up,the panel In the house is main lug,do I need to change panel to auto transfer so as not to backfeed utility.

 

[tom baker]

Working on a mobile home,they want a generator back up,the panel In the house is main lug,do I need to change panel to auto transfer so as not to backfeed utility.

You need either a listed manual transfer switch or auto.
That is homeowners choice based on cost, if auto the generator must be able to carry entire calculated load. For manual, you can have a 5 KW generator on a 200 amp panel
Suggest reading the rules in Art 702.

 

[qcroanoke]

Working on a mobile home,they want a generator back up,the panel In the house is main lug,do I need to change panel to auto transfer so as not to backfeed utility.

There has to be overcurrent/ground fault protection in front of it.
Probably just outside of the home.
look there and see what you have. if it has more circuit space available you may be able to get a utility/generator interlock device to use.

 

[JFletcher]

A manual interlock kit will not work on a MLO panel as they physically prevent the main and generator breakers from being on at the same time, and that panel has no main.

I'd use a manual transfer switch unless the HO is willing to go with a completely automated setup. No point in an ATS if they're using a portable generator.

 

[qcroanoke]

A manual interlock kit will not work on a MLO panel as they physically prevent the main and generator breakers from being on at the same time, and that panel has no main.

I'd use a manual transfer switch unless the HO is willing to go with a completely automated setup. No point in an ATS if they're using a portable generator.

"There has to be overcurrent/ground fault protection in front of it.
Probably just outside of the home.
look there and see what you have."


I didn't say it would.

 

[JFletcher]

"There has to be overcurrent/ground fault protection in front of it.
Probably just outside of the home.
look there and see what you have."


I didn't say it would.

I didnt say you did... more musing to myself that a standard cheapie manual interlock kit wont work on the panel, which was my first thought.

 

[augie47]

You might have an interesting inspection with the MLO panel as it appears to be a violation of 550.(B).
Nevertheless, in regard to your question, you need to install some provision to assure there is no backfeed. Among the possibilities would be: (a) a service rated automatic transfer or manual transfer switch; (b) a non-service rated trasnfer switch protected by the service overcurrent device, or, (c) as mentioned, an approved interlock mechanism between the backfeed and utility breaker.

 

[Smart $]

You might have an interesting inspection with the MLO panel as it appears to be a violation of 550.(B).
...

550.xx(B)?


I'm thinking 550.11 and (A) thereunder...

550.11 Disconnecting Means and Branch-Circuit Protective
Equipment. The branch-circuit equipment shall be
permitted to be combined with the disconnecting means as
a single assembly. Such a combination shall be permitted to
be designated as a panelboard. If a fused panelboard is
used, the maximum fuse size for the mains shall be plainly
marked with lettering at least 6 mm (1⁄4 in.) high and visible
when fuses are changed.

Where plug fuses and fuseholders are used, they shall
be tamper-resistant Type S, enclosed in dead-front fuse
panelboards. Electrical panelboards containing circuit
breakers shall also be dead-front type.

Informational Note: See 110.22 concerning identification​

of each disconnecting means and each service, feeder, or​

branch circuit at the point where it originated and the type​

marking needed.​

(A) Disconnecting Means. A single disconnecting means
shall be provided in each mobile home consisting of a circuit
breaker, or a switch and fuses and its accessories installed
in a readily accessible location near the point of
entrance of the supply cord or conductors into the mobile
home. The main circuit breakers or fuses shall be plainly
marked “Main.” This equipment shall contain a solderless
type of grounding connector or bar for the purposes of
grounding, with sufficient terminals for all grounding conductors.
The terminations of the grounded circuit conductors
shall be insulated in accordance with 550.16(A). The
disconnecting equipment shall have a rating not less than
the calculated load. The distribution equipment, either circuit
breaker or fused type, shall be located a minimum of
600 mm (24 in.) from the bottom of such equipment to the
floor level of the mobile home.

Informational Note: See 550.20(B) for information on disconnecting​

means for branch circuits designed to energize​

heating or air-conditioning equipment, or both, located outside​

the mobile home, other than room air conditioners.​

A panelboard shall be rated not less than 50 amperes
and employ a 2-pole circuit breaker rated 40 amperes for a
40-ampere supply cord, or 50 amperes for a 50-ampere
supply cord. A panelboard employing a disconnect switch
and fuses shall be rated 60 amperes and shall employ a
single 2-pole, 60-ampere fuseholder with 40- or 50-ampere
main fuses for 40- or 50-ampere supply cords, respectively.
The outside of the panelboard shall be plainly marked with
the fuse size.

The panelboard shall be located in an accessible location
but shall not be located in a bathroom or a clothes
closet. A clear working space at least 750 mm (30 in.) wide
and 750 mm (30 in.) in front of the panelboard shall be
provided. This space shall extend from the floor to the top
of the panelboard.

(B) Branch-Circuit Protective Equipment. ....