Isolation transformer???

[jayaredee]

we removed this from an industrial space that was leased to someone who started building a recording studio and then ran out of money...they installed it on the feeders to a sub panel that was never completely wired or used.

I'm assuming it would be for isolation/noise reduction? or is it intended to protect against voltage surges on sensitive recording equipment?

I saw one website that listed this model brand new for about $1000. Do you think I can get a good price for this one? Where should I list it? didn't see anything like it on the 'bay'...

 

[dereckbc]

Isolation transformer for CMR or Common Mode Noise Reduction

 

[beanland]

General Purpose

General Purpose

A transformer will do little to block surges, under-voltage, dips, over-voltage, spikes, etc. It can halp for higher-frequency and common-mode issues. This is just an isolation transformer.

 

[stickboy1375]

I just ripped one of those out of a lawyers office, the wiring was pretty bad on how they had it setup, but whoever did the install was trying to provide IG receptacles... The receptacles were easy to find though, meter would read 58 volts from hot to ground... :roll:

 

[jrannis]

We just installed one. It was cheaper than trying to get a neutral to the spot where we needed it.
BTW the 10kva was about $275.00

 

[jayaredee]

BTW the 10kva was about $275.00

Wow, I guess the site I saw it on was a little over priced?? Where'd you get yours?

 

[catchtwentytwo]

I just ripped one of those out of a lawyers office, the wiring was pretty bad on how they had it setup, but whoever did the install was trying to provide IG receptacles... The receptacles were easy to find though, meter would read 58 volts from hot to ground... :roll:

Just curious, did the installer wire it as 240 primary/120 volt secondary? I once saw one done as 120/120 with the neutrals connected to a common ground point.

 

[jrannis]

Wow, I guess the site I saw it on was a little over priced?? Where'd you get yours?

CED Raybro Hollywood Fl

 

[stickboy1375]

Just curious, did the installer wire it as 240 primary/120 volt secondary? I once saw one done as 120/120 with the neutrals connected to a common ground point.

This was a 120/120 fed by a 1pole 30 amp breaker with the ground cut off, they then installed a ground rod for all the new receptacles... :roll:

 

[hurk27]

This was a 120/120 fed by a 1pole 30 amp breaker with the ground cut off, they then installed a ground rod for all the new receptacles...

Sure hope they had the grounding also bonded to the neutral on the secondary250.30(A)(1), because a ground rod will not provide a low enough impedance for fault path, I have installed several of these and also the 120/240--120/60 volt types. But mainly to prevent any ground loops in audio systems or communication systems.

Also seen them used to isolate shore power for metal hull boats, but keep in mind all grounding electrodes have to be bonded together to form one grounding electrode system 250.50

 

[stickboy1375]

Sure hope they had the grounding also bonded to the neutral on the secondary250.30(A)(1), because a ground rod will not provide a low enough impedance for fault path, I have installed several of these and also the 120/240--120/60 volt types. But mainly to prevent any ground loops in audio systems or communication systems.

Also seen them used to isolate shore power for metal hull boats, but keep in mind all grounding electrodes have to be bonded together to form one grounding electrode system 250.50

Nope, they didnt... all the receptacles read around 56v from hot to ground.

 

[drew33]

I just replaced one of these in our control center which it powered a hvac unit. I wondered why the heck they put this on a 240v prim to a 240v sec. When you said radio i thought omg. It answered my question because our control center is the hub of our communications at our corrections fac. It had a double pole 30a breaker. $1,300 lol for x-former.

 

[billklus]

Need to derive neutral from straight 3phase feed.

Need to derive neutral from straight 3phase feed.

I want to feed a 480/277 volt small emergency lighting panel from a nearby 480/277 volt dist. panel. The problem is there is no neutral available in the dist. panel. Can I feed an isolation transformer and derive a neutral through XO bond to feed my sub panel Legally???? There is no other feed anywhere close..... Panel I'm installing is only a 30 amp main.

Thanks......

 

[cycotcskir]

ACME! Beep, Beep.............Boom


View attachment 3238

 

[LarryFine]

Can I feed an isolation transformer and derive a neutral through XO bond to feed my sub panel Legally???? There is no other feed anywhere close..... Panel I'm installing is only a 30 amp main.

You absolutely may. Get a 480D-to-480Y/277 unit. Don't forget about bonding via a GEC.

 

[Pierre C Belarge]

You absolutely may. Get a 480D-to-480Y/277 unit. Don't forget about bonding via a GEC.

As per 250.30, the GEC for a separately derived system is either steel in the area being served or water pipe within 5 ft where it enters the building.

 

[kbsparky]

We used a similar transformer to solve a heating element problem embedded in some floor tiles.

The heating element was tripping out the built-in GFCI in the thermostat, and short of busting up the floor and starting over, it was a viable solution.

We ended up feeding 240 Volts in, and 120 Volts out, and the nuisance tripping ceased. :grin:

Floor heating now works just fine. :smile: