Farm transfer switch w/ triplex

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aglick87

Member
I live in a agricultural area. Most farms have a common center pole service w/ triplex feeding the house, barn, garages, outbuildings, etc. They later get the idea of adding transfer switches at the centerpole. To do one of these correctly, are we talking about ocp at the pole w/ a transfer switch. Then replacing all of the triplex with quad. Then rewiring all of the panels to seperate the grounding & grounded conductors? The farming dollar here has been poor for some time. I don't see them going for this but I will not do an improper installation knowingly. I have seen countless installs just interupted into the service with 4/0 seu cable. Thoughts? Ideas?
 

ceb58

Senior Member
Location
Raeford, NC
Sounds like the right thing to do. I will ask
The farming dollar here has been poor for some time.
Are the farmers telling this or is it a fact. Born and raised on a farm and all my life I have heard the farmers complaining about not making any money. While they were on the way to buy a new truck and tractor. Their worse than electricians;)
 

qcroanoke

Sometimes I don't know if I'm the boxer or the bag
Location
Roanoke, VA.
Occupation
Engineering
When is the road trip to Canada? Then we can change you screen name to ballsforzenoff:D
Haven't heard another word about it! Which is good with me if it's any colder there than it is here I don't wanna go!
With wind chill it's about 3 below!
 

aglick87

Member
Has anyone else ran into a situation like this? How far am I required to take it to make things right. I was asked to replace the rusted out nema 1 transfer switch. Could keep branching out into replacing the triplex, seperating grounded & grounding conductors, driving ground rods at each panel, puting in the correct amperage breakers. Where does my liablility stop when a property has so much wrong. How far should I go to correct things.
 

jxofaltrds

Senior Member
Location
Mike P. Columbus Ohio
Occupation
ESI
I live in a agricultural area. Most farms have a common center pole service w/ triplex feeding the house, barn, garages, outbuildings, etc. They later get the idea of adding transfer switches at the centerpole. To do one of these correctly, are we talking about ocp at the pole w/ a transfer switch. Then replacing all of the triplex with quad. Then rewiring all of the panels to seperate the grounding & grounded conductors? The farming dollar here has been poor for some time. I don't see them going for this but I will not do an improper installation knowingly. I have seen countless installs just interupted into the service with 4/0 seu cable. Thoughts? Ideas?
Could 250.32(B) Exception help you?
 

magoo66

Member
Article 547 requires a site isolation device, I don't recall it requiring any OCP. I have used service rated transfer switches mounted on the distribution meter pole and left all the triplex and panelboards alone. I haven't done one since the '08 code was adopted though and don't know how the new "feeder rule" would apply. As far as working on farms, even when times were good, they were crying poor.
 

aglick87

Member
That exception may help us here. I will have to check on the continuous metallic paths. There may be milk pipeline or other metal piping connecting the buildings. They way it reads, I may not have to replace all of the triplex, just the wiring to the panels where they have metallic return current paths between. Thanks for the reference.
 

renosteinke

Senior Member
Location
NE Arkansas
I don't see how installing a transfer switch -presumably for bringing in power from another source, such as a generator- would affect the downstream distribution arrangements.

Now, here's how I see the topic ... keep in mind that the NEC hasn't quite come around to this perspective :

The real question is: where does the 'service' end and the 'distribution' begin? When there's only the PoCo service, the answer is easy: at the first ("main" fuses or breaker) overcurrent device.

To me, thiis suggests that every power source needs to have some form of OCPD, and that your 'service point' would then technically move to where the different 'services' come together. That is, at the transfer switch.

(Keep in mind that I also advocate 'separately derived systems,' also known as where you also switch the neutral.)

Even if you are using some other form of generation - say, solar panels - where you actually want to be able to back-feed the PoCo, I really like the idea of a single means to disconnect the 'distribution' system from ALL power sources. In such an arrangement, I can see defining this disconnect as the 'service point.'

Farms are allowed a slight allowance by the NEC, where you can have a single disconnect serving all the buildings. Fari enough ... but, as I see it, the feeds to these other buildings is part of the distribution system, and an issue separate from the transfer switch issue.

Only recently has the NEC made plain that such feeds ought to be 4-wire (both neutral and ground). With an older arrangement, I do not see the installation of a transfer switch as requiring that the entire distribution network be brought up to date.
 

aglick87

Member
The ocp is to maintain the 200A rating of the transfer switch. without it, there could potentially be the sum of all of the panel mains running through the switch. I know it's not likely but i have seen 200A mains trip in the summer when the all the fans & cooling compressors are running. There isn't one there now, but I think it's a good idea.
 

jxofaltrds

Senior Member
Location
Mike P. Columbus Ohio
Occupation
ESI
That exception may help us here. I will have to check on the continuous metallic paths. There may be milk pipeline or other metal piping connecting the buildings. They way it reads, I may not have to replace all of the triplex, just the wiring to the panels where they have metallic return current paths between. Thanks for the reference.
If the metal lines are continuous, you maybe able to 'isolate' them.
 

ptonsparky

Senior Member
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
Electrical Contractor
Put an unfused transfer switch on the pole or center point. That is what most of the utilities use in this area. Three wire to all the buildings. You are not changing a current path or making an existing farmstead more dangerous in any way shape or form. Not to many farmers no matter how rich will go for a $30000 bill vs $3000.
 

Smart $

Esteemed Member
Location
Ohio
Put an unfused transfer switch on the pole or center point. That is what most of the utilities use in this area. Three wire to all the buildings. You are not changing a current path or making an existing farmstead more dangerous in any way shape or form. Not to many farmers no matter how rich will go for a $30000 bill vs $3000.
Is a non-service-entrance-rated transfer switch (i.e. no OCPD) permitted on the premises side of the service point? My gut says no... but haven't checked ink levels yet ;)

Exactly where is the service point for this installation? Are the triplexes all service drops?
 

kwired

Electron manager
Location
NE Nebraska
Put an unfused transfer switch on the pole or center point. That is what most of the utilities use in this area. Three wire to all the buildings. You are not changing a current path or making an existing farmstead more dangerous in any way shape or form. Not to many farmers no matter how rich will go for a $30000 bill vs $3000.
Is a non-service-entrance-rated transfer switch (i.e. no OCPD) permitted on the premises side of the service point? My gut says no... but haven't checked ink levels yet ;)

Exactly where is the service point for this installation? Are the triplexes all service drops?
I think ptonsparky is probably talking about (non listed) combination meter/transfer switch that many POCO's install around this part of the country. There is no overcurrent device, double throw switch, multiple load lugs, and a meter socket. Commonly found in 200 or 400 amp sizes around here. On farms they typically install a pole with either a meter/main or one of these double throw units (usually for additional charge, but cheaper than any contractor can legally install any transfer equipment (especially of that size). This is their service point and anything on the load side they will not work on.
 

kwired

Electron manager
Location
NE Nebraska
Would you be asking the same question if installing the transfer switch in or on a building instead of a pole and there were other buildings supplied from the first? Existing feeders supplying separate buildings that do not contain an equipment grounding conductor do not have to have an EGC added when changing equipment at the supply or source - if it was acceptable prior to 2008 NEC to not install the EGC.

See exception to 250.32(B)
 
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