# Disconnect tap question



## Eric23 (Feb 12, 2018)

Eric23 said:


> I have a customer that took over a commercial space and is adding a second 480v 20amp HVAC unit on the roof. There is an existing 480v 20amp unit in place fed off a fused disconnect that's tapped off the riser before it hits the transformer. The problem is I have no room for another tap to add a disconnect for the new unit. Trying to figure out what my best options are for feeding a second disconnect ? Below is a pic of the existing disconnect
> 
> 
> 
> ...


I'm thinking it might be easier to take this disconnect out and replace it with a small 100-amp 480-volt panel. 

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## telsa (May 22, 2015)

Your tap conductors are huge.


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## Eric23 (Feb 12, 2018)

telsa said:


> Your tap conductors are huge.


I didn't do that it was existing

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## Eddie702 (Aug 7, 2015)

Adding a panel will work.

Since your feeders are plenty big enough (I assume they feed nothing else) why not put in a short section of aux gutter to tap from and add a second disconnect for the added unit??


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## Eric23 (Feb 12, 2018)

Eddie702 said:


> Adding a panel will work.
> 
> Since your feeders are plenty big enough (I assume they feed nothing else) why not put in a short section of aux gutter to tap from and add a second disconnect for the added unit??


Eddie702 I thought about that as I was going home. I'll probably bring those feeders in to a small trough and splice them out Polaris and add another disconnect.

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## MechanicalDVR (Dec 29, 2007)

I think the trough idea and second disco is the way to go.


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## telsa (May 22, 2015)

Me too... as I have a hard time imagining other 480 3-phase loads.

Tiny, cheap, 480 3-phase panels don't exist.


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## cabletie (Feb 12, 2011)

We really need to see a one line for this set up. 

The first rule of taps is you can't tap a tap. 

This branch circuit was originally sized to feed a transformer? Then a disconnect was added for a roof top unit?

So the original tap landed in a single set of fuses. Tapping that tap would violate the first tap by not making it land in a single set of fuses. 

Maybe a panel with a main breaker would be ok, but it still seams a little weird.


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## MechanicalDVR (Dec 29, 2007)

cabletie said:


> We really need to see a one line for this set up.
> 
> The first rule of taps is you can't tap a tap.
> 
> ...


And expensive!


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## Eric23 (Feb 12, 2018)

cabletie said:


> We really need to see a one line for this set up.
> 
> The first rule of taps is you can't tap a tap.
> 
> ...


Cabletie yes this is tapped in a trough right before the transformer... I know you can't tap a tap which is why I was originally going to try the panel. What if I redo the tap and use Polaris connectors to make two feeds for the two discos

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## Eric23 (Feb 12, 2018)

Eric23 said:


> Cabletie yes this is tapped in a trough right before the transformer... I know you can't tap a tap which is why I was originally going to try the panel. What if I redo the tap and use Polaris connectors to make two feeds for the two discos
> 
> Sent from my Nexus 6P using Tapatalk


The trough is just packed as it is there's really no room otherwise I would just make another tap 

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## Eric23 (Feb 12, 2018)

Eric23 said:


> The trough is just packed as it is there's really no room otherwise I would just make another tap
> 
> Sent from my Nexus 6P using Tapatalk


Would this count as a single tap ?









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## telsa (May 22, 2015)

Eric, you're making me think that you're going to have re-build more than just this disconnect.

BTW, is there any way that you could drop in a 60A frame size 480VAC disconnect right where the existing 30A frame size is?

Then you could run taps to twin 30A disconnects, after the 60A disco -- re-using the existing one seen in the photo.


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## Eric23 (Feb 12, 2018)

telsa said:


> Eric, you're making me think that you're going to have re-build more than just this disconnect.
> 
> BTW, is there any way that you could drop in a 60A frame size 480VAC disconnect right where the existing 30A frame size is?
> 
> Then you could run taps to twin 30A disconnects, after the 60A disco -- re-using the existing one seen in the photo.


I could probably fit a 60a disco in there but then you're talking about tapping off the load side of the 60 to feed two 30's ? Can you tap off the load side in the disco ? I've never see that done ?

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## cabletie (Feb 12, 2011)

Did the last guy put in a fused disconnect before the original transformer?

To me if there was going to be a tap, you would need all the taps landed in a single set of fuses or single circuit breaker. So if there was a trough you could tap it three times as long as each set lands at a single set of fuses or circuit breaker. That would include the transformer, not to mention possibly resizing the original feeder and breaker.


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## telsa (May 22, 2015)

Eric23 said:


> I could probably fit a 60a disco in there but then you're talking about tapping off the load side of the 60 to feed two 30's ? Can you tap off the load side in the disco ? I've never see that done ?
> 
> Sent from my Nexus 6P using Tapatalk


There is sure to be enough room for ILSCO// Polaris taps at the bottom of the 60A disco. You're talking #6 and twin #10 conductors. No biggie.

These daughter taps would promptly run off to 30A frame size safety switches... as in you'd re-use the one in the photo. 

You'd have 25 feet of grace between Mr. 60A and its daughters.

This would obey the NEC.


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## Eric23 (Feb 12, 2018)

telsa said:


> There is sure to be enough room for ILSCO// Polaris taps at the bottom of the 60A disco. You're talking #6 and twin #10 conductors. No biggie.
> 
> These daughter taps would promptly run off to 30A frame size safety switches... as in you'd re-use the one in the photo.
> 
> ...


Tesla thank you that's probably the most cost and time effective way to do this...

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## Eric23 (Feb 12, 2018)

This place is a mess the more things I open up the more problems I find.. they have 2 single phase 480v 30a water heaters and the disconnects for them in the electrical room are tapped off the the load side lugs in a fused 100a disco that feeds the transformer for the space with #12 wire 

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## Eric23 (Feb 12, 2018)

Eric23 said:


> This place is a mess the more things I open up the more problems I find.. they have 2 single phase 480v 30a water heaters and the disconnects for them in the electrical room are tapped off the the load side lugs in a fused 100a disco that feeds the transformer for the space with #12 wire
> 
> Sent from my Nexus 6P using Tapatalk


Then they ran number 10s off the load side of the hot water disconnects to a box in the ceiling continued off to the space with number #12 then came out of that box to feed the disconnect next to the actual water heater units with number 10

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## Cow (Jan 16, 2008)

Eric, 

I do A LOT of farm work, so believe me, I see some stupid stuff.

Just remember one thing. You and you alone set the standard of the work you do. 

I would not hesitate to explain the circumstances of the situation in laymens terms as best you can while letting them know what it's going to take to do it right. It does not matter how billy bob wired it 10 years ago, it's wrong, and it makes no sense to compound the problem by adding onto it.

I'd say 98% of our work is from repeat customers, so I think it has payed off for us.

It's not necessarily fun taking a hard line, but hopefully your customer understands and appreciates your experience in explaining what needs to be done to make this right.

Good luck.


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## Eddie702 (Aug 7, 2015)

I agree with @Cow. It sucks we have all been their. Time to take a step back and a deep breath and fix it all. Problems just get compounded and it becomes a service nightmare down the road


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## cl2sparky (Jan 3, 2017)

Eric23 said:


> Cabletie yes this is tapped in a trough right before the transformer... I know you can't tap a tap which is why I was originally going to try the panel. What if I redo the tap and use Polaris connectors to make two feeds for the two discos
> 
> Sent from my Nexus 6P using Tapatalk


Is there a disconnect between first tap and transformer? If so, tap rule should apply. 

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