500VA isolation transformer by PHC Enterprise, Inc., showing front view of the ISO-500 device with power input and output terminals.

Back view of PHC Enterprise 500VA isolation transformer ISO-500, showing terminals and cooling vents for 117VAC to 117VAC power conversion.

500VA isolation transformer by PHC Enterprise, Inc., converting 117VAC to 117VAC with durable metal enclosure.

500VA Isolation Transformer 117VAC to 117VAC | ISO-500

Name: 500VA Isolation Transformer 117VAC to 117VAC | ISO-500
Rating: 4.78 (51 reviews)

by PHC Enterprise, Inc.

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The ISO-500 is a professional 500VA isolation transformer engineered for controlled AC power in electronics repair, oscilloscope troubleshooting, engineering R&D, educational labs, and audio testing. With 117VAC input and 117VAC isolated output, a floating output design, two three-slot output receptacles with unconnected ground contacts, and rugged steel housing, it provides a dedicated isolated source for bench work.

Why Choose the ISO-500 Isolation Transformer?

True Galvanic Isolation: Physical separation between the AC line and the output creates a floating source for appropriate electronics testing and repair setups.
Floating Output for Qualified Bench Testing: Provides an isolated AC source for the device under test. Isolation does not make energized circuits safe to touch. Follow appropriate isolated-power procedures and never defeat required safety grounds.
500VA Bench Capacity: Provides 500VA of isolated AC power and includes a 5A fast-blow fuse for circuit protection.
Rugged Professional Design: Heavy-duty steel housing and two three-slot output receptacles with unconnected ground contacts suit repair benches, laboratories, and technical workstations.

Technical Specifications

Part: ISO-500
Input Voltage: 117VAC, 60Hz; polarized two-pin input plug
Output Voltage: Physically isolated, 60Hz; 117VAC ±5% at no load and 110VAC ±5% at full load, per the specification sheet
Maximum Power Rating: 500VA
Protection: 5A Fast-Blow Fuse (GMA-5A-5)
Output Outlets: Two three-slot receptacles; ground contacts not connected
Output Grounding: Floating Output with No Input-to-Output Ground Bond
Dimensions: 8.3" (L) x 5.6" (W) x 4.3" (H)
Weight: 11.7 lbs

Common Applications — Who Is This For?

Oscilloscope and Test Equipment: Isolate the device under test from the AC line to help reduce unintended grounding conflicts during measurements.
Engineering R&D: Provide a dedicated isolated source for prototyping and sensitive hardware testing.
Educational Electronics Labs: Demonstrate transformer isolation and AC measurement concepts under qualified supervision.
Audio Engineering: Evaluate ground-loop-related noise in measurement and signal-processing setups.
Electronics Repair: Support troubleshooting of AC-powered equipment in professional repair environments.

Frequently Asked Questions

Q: What does the ISO-500 isolation transformer do?
A: Part ISO-500 accepts 117VAC at 60Hz and provides an output physically isolated from the incoming AC line. The specification sheet lists 117VAC ±5% at no load and 110VAC ±5% at full load. The total connected load must not exceed 500VA.

Q: Why use the ISO-500 with an oscilloscope?
A: Its floating output can help reduce unintended ground paths when the device under test is connected to grounded measurement equipment. Use qualified electrical-safety procedures and do not defeat the oscilloscope safety ground.

Q: Is the ISO-500 output grounded?
A: The output is floating and has no input-to-output ground bond. The output receptacles have three slots, but their ground contacts are not connected and do not provide an earth-ground path, so the unit should be used only by people trained in isolated-power safety.

Q: How much power can the ISO-500 supply?
A: The ISO-500 is rated for a maximum load of 500VA and includes a 5A fast-blow fuse. Keep the connected equipment within the transformer rating and follow its operating instructions.

Q: Does the ISO-500 change the voltage?
A: It is intended for nominal 117VAC-to-117VAC isolation, not voltage conversion or regulation. Output voltage varies with load: the specification sheet lists 117VAC ±5% at no load and 110VAC ±5% at full load.

5 stars: 46 (90%)
4 stars: 2 (4%)
3 stars: 1 (2%)
2 stars: 1 (2%)
1 star: 1 (2%)

Some of the reviews shown are from related products the merchant grouped with this one.

Nicely built, solid BUT...

They put normal fuses in it and the directions specify slo-blo, so in the process of checking it out, I blew a fuse. I just purchased the specified ones from Amazon, and no more problems. I'd buy it again, but come on....put the correct fuses in it.!

Works. Looks good too.

More compact with the toroid transformer.

Professional 1000VA Isolation Transformer | 117VAC to 117VAC - ISO-1000

Work as described.

Excellent Packing

Unit works exactly as it should. This unit is heavy, it was double boxed along with bubble wrap and fitted inserts. Outstanding!

Isolated ok

PHC 500VA Isolation Transformer, 117VAC

A true isolation transformer. Simplistic and effective. Outstanding.

500 VA Isolation Transformer

Item packaged well, shipping was fine, working as expected. Happy with purchase.

1000VA Isolation Transformer

Fast delivery, exceptional packaging, and sturdy construction. Have used it a few times and it performs as it should. I will purchase additional items as the need arises.

Looks good

And, it' heavy, but I havent used it yet.

Packed and shipped well.

Very well built. Works perfectly. Good value.

Superlative

I ordered a 20 some pound transformer and was thinking I would be lucky if it arrived unscathed. It was in perfect condition mainly due to the outstanding way it was packed. Triple boxed with foam between each layer. It was truly gorilla proof. And the product inside is well made and reasonable price. What a contrast to the business as usual companies that I normally deal with. Thank you.

Thank you for your business and for taking the time to leave such a wonderful review! We are thrilled to hear that your 1000VA Isolation Transformer arrived in perfect condition and that you were impressed with the packaging. We take great care in ensuring that our products are well-protected during shipping. We are also glad to know that you found our product to be well-made and reasonably priced. Thank you for choosing our company and we hope to serve you again in the future.

Happy Holidays!

A genuinely amazing buying experience with AC DC Powershack. The isolation transformer was packed with meticulous care—thank you! Owner Patrick is fantastic and made communication effortless. Top marks all around.

We appreciate your support and kind words. Happy Holidays!

Works great

Great to hear it is working for your application. Appreciate the business and review. Have a great day!

excellent quality

This is the perfect addition to my shop for doing vintage radio troubleshooting. The isolation transformer works fine and appears to be well made.

Thank you for taking the time to leave a review for our 500VA Isolation Transformer. We are delighted to hear that it is the perfect addition to your shop for vintage radio troubleshooting and that it is working well for you. Our team takes pride in providing excellent quality products and we are glad to know that it appears to be well made.

Have a great day!

Works great

Now a staple component to my electronic desk.

Thank you so much for your business and for taking the time to leave a review. We are thrilled to hear that our 300VA Isolation Transformer is now a staple component on your electronic desk. It's always a pleasure to know that our products are meeting the needs of our customers. Thank you again for your support!

Best,
Hans

Very nice

This is a real isolation transformer. Keeps me safe when doing my repairs.

Thank you for taking the time to leave a review for our 500VA Isolation Transformer. We are happy to hear that it has been working well for you and providing the safety you need during repairs. We appreciate your support and hope to continue providing you with quality products in the future.

Well designed product

I got the 500VA small Isolation Transformer for doing refurbishing of old short wave radios. The unit is attractive, compact, very well designed and has a reasonable price. I am completely happy with my purchase.

300VA Isolation Transformer, 117VAC to 117VAC

Thank you for your review of our 300VA Isolation Transformer. We are glad to hear that you are satisfied with your purchase and that it meets your needs. If you have any further questions or concerns, please don't hesitate to reach out to us. Thank you for choosing our product.

300VA Isolation Transformer, 117VAC to 117VAC

Hi there! Thank you for your business and for taking the time to leave a review for our 300VA Isolation Transformer. We're glad to hear that it met your needs and we hope it continues to serve you well. Have a great day!

300VA Isolation Transformer, 117VAC to 117VAC

Thanks for the 300VA Isolation Transformer, 117VAC to 117VAC. The shipping was fast look great and is heavy. transformer was a great price would buy from AC-DC PowerShack again.

Thank you for your kind review! We are thrilled to hear that you are happy with your 300VA Isolation Transformer. Our team always strives to provide fast shipping and quality products at affordable prices. We are always happy to hear when our customers are 100% satisfied. Thank you for choosing AC-DC PowerShack, we appreciate your business.

Fast, efficient, and excellent price.
Thanks

Hello Roberto,

Thank you for your purchase and taking the time to leave a review. Have a great day!

Very loud hum

Unfortunately, this transformer hums louder than the hum I'm trying to eliminate from my amplifier. It actually made me a little nervous to use so I'm getting rid of it. It was on sale though, so that was a plus.

Thanks for taking the time to leave a honest review. Please look out for our email to see if we can resolve this issue. The isolation transformer usually would not have a hum unless it is defective or it is running near or at the rated wattage.

A Workbench Essential

I use this to isolate my Powerstat and Dimbulb on my workbench when testing electronic gear. 300 VA is all I need because of the Dimbulb limiter and it works as advertised.

Thank you for your review! We're thrilled to hear that our 300VA Isolation Transformer has become an essential tool on your workbench. We're glad it's working as advertised and meeting your needs.

Better than expected

For the price point, this is a great deal! The order was well packaged and not damaged at all, unlike some other vendors that I have bought from. The transformer was not advertized as a toroid, but it is which is a big plus. It is properly mounted to the case with a good bolt, and isn't going anywhere. The case itself is decently thick sheet metal. Solder connections on the inside were good, wiring was tidy, and nothing needed rework. Input side had a two-pole switch and a glass fuse. Output has a switched breaker. All in all, this is a really nice and well built unit and you can't beat the price.

Thank you for taking the time to leave such a positive review of our 1000VA Isolation Transformer. We are delighted to hear that it exceeded your expectations in terms of quality and packaging. We take pride in providing well-built products at a great price. Our team works hard to ensure that every detail, from the toroid design to the sturdy case and clean wiring, meets our high standards. We appreciate your business and hope to continue exceeding your expectations in the future.

Isolation transformer

Needed for bench work on some older type tube receivers. Fit my needs also the two outlets provided a plus. Received quickly and well packed. Completive pricing
and reasonable shipping would use again.

Thank you for choosing our product and for sharing how you utilize the isolation transformer with the community. We hope to have the opportunity to serve you again in the future!

Assume it isolates, but dd not cure my noise problem

There are no guarantees that a transformer will cure any noise issue, and this did not. Also, because it hums, it is introducing noise into the room. I did not expect this. I am debating on whether to return it, redeploy to another area, or to upgrade to a balanced power solution, etc. It has serious heft, so I am sure its a good isolation transformer. I feel like it may have opened up/uncompressed the low end quite a bit, but can not measure this accurately.

Thank you for sharing your experience with our 1000VA Isolation Transformer. We apologize that it did not fully resolve your noise issue. While we cannot guarantee that our transformer will solve all noise problems, we do stand by its quality and effectiveness as an isolation transformer.

Regarding the hum, I will reach out to you to see if we can remedy the problem or provide a solution to your satisfaction.

We appreciate your feedback and are always looking for ways to improve our products.

Great product

It did a good job as advertised. I was getting a hum when I turned on my subwoofer. I plugged the sub directly to the isolation transformer. It decreased it by about 90%. Maybe if I plug my sub into my power conditioner and then plug the power conditioner into the transformer it might eliminate the hum completely. I have not tried it yet. Have not had time,but the hum is barely noticeable now. I have to get very close to the sub to detect it. Very happy even with the 90% hum reduction
I'll will definitately keep it
Great product..

Thank you for taking the time to leave a review for our 500VA Isolation Transformer. We are so glad to hear that it has been working as advertised and has greatly reduced the hum from your subwoofer.

If you have any further questions or concerns, please don't hesitate to reach out to us. We truly appreciate your support and hope you continue to enjoy our product.

5 stars: 46 (90%)
4 stars: 2 (4%)
3 stars: 1 (2%)
2 stars: 1 (2%)
1 star: 1 (2%)

Some of the reviews shown are from related products the merchant grouped with this one.

Nicely built, solid BUT...

Works. Looks good too.

More compact with the toroid transformer.

Professional 1000VA Isolation Transformer | 117VAC to 117VAC - ISO-1000

Work as described.

Excellent Packing

Unit works exactly as it should. This unit is heavy, it was double boxed along with bubble wrap and fitted inserts. Outstanding!

Isolated ok

PHC 500VA Isolation Transformer, 117VAC

A true isolation transformer. Simplistic and effective. Outstanding.

500 VA Isolation Transformer

Item packaged well, shipping was fine, working as expected. Happy with purchase.

1000VA Isolation Transformer

Fast delivery, exceptional packaging, and sturdy construction. Have used it a few times and it performs as it should. I will purchase additional items as the need arises.

Looks good

And, it' heavy, but I havent used it yet.

Packed and shipped well.

Very well built. Works perfectly. Good value.

Superlative

Happy Holidays!

We appreciate your support and kind words. Happy Holidays!

Works great

Great to hear it is working for your application. Appreciate the business and review. Have a great day!

excellent quality

This is the perfect addition to my shop for doing vintage radio troubleshooting. The isolation transformer works fine and appears to be well made.

Have a great day!

Works great

Now a staple component to my electronic desk.

Best,
Hans

Very nice

This is a real isolation transformer. Keeps me safe when doing my repairs.

Well designed product

300VA Isolation Transformer, 117VAC to 117VAC

300VA Isolation Transformer, 117VAC to 117VAC

Thanks for the 300VA Isolation Transformer, 117VAC to 117VAC. The shipping was fast look great and is heavy. transformer was a great price would buy from AC-DC PowerShack again.

Fast, efficient, and excellent price.
Thanks

Hello Roberto,

Thank you for your purchase and taking the time to leave a review. Have a great day!

Very loud hum

A Workbench Essential

I use this to isolate my Powerstat and Dimbulb on my workbench when testing electronic gear. 300 VA is all I need because of the Dimbulb limiter and it works as advertised.

Thank you for your review! We're thrilled to hear that our 300VA Isolation Transformer has become an essential tool on your workbench. We're glad it's working as advertised and meeting your needs.

Better than expected

Isolation transformer

Thank you for choosing our product and for sharing how you utilize the isolation transformer with the community. We hope to have the opportunity to serve you again in the future!

Assume it isolates, but dd not cure my noise problem

Regarding the hum, I will reach out to you to see if we can remedy the problem or provide a solution to your satisfaction.

We appreciate your feedback and are always looking for ways to improve our products.

Great product

Thank you for taking the time to leave a review for our 500VA Isolation Transformer. We are so glad to hear that it has been working as advertised and has greatly reduced the hum from your subwoofer.

If you have any further questions or concerns, please don't hesitate to reach out to us. We truly appreciate your support and hope you continue to enjoy our product.

5 stars: 46 (90%)
4 stars: 2 (4%)
3 stars: 1 (2%)
2 stars: 1 (2%)
1 star: 1 (2%)

Some of the reviews shown are from related products the merchant grouped with this one.

Nicely built, solid BUT...

Works. Looks good too.

More compact with the toroid transformer.

Professional 1000VA Isolation Transformer | 117VAC to 117VAC - ISO-1000

Work as described.

Excellent Packing

Unit works exactly as it should. This unit is heavy, it was double boxed along with bubble wrap and fitted inserts. Outstanding!

Isolated ok

PHC 500VA Isolation Transformer, 117VAC

A true isolation transformer. Simplistic and effective. Outstanding.

500 VA Isolation Transformer

Item packaged well, shipping was fine, working as expected. Happy with purchase.

1000VA Isolation Transformer

Fast delivery, exceptional packaging, and sturdy construction. Have used it a few times and it performs as it should. I will purchase additional items as the need arises.

Looks good

And, it' heavy, but I havent used it yet.

Packed and shipped well.

Very well built. Works perfectly. Good value.

Superlative

Happy Holidays!

We appreciate your support and kind words. Happy Holidays!

Works great

Great to hear it is working for your application. Appreciate the business and review. Have a great day!

excellent quality

This is the perfect addition to my shop for doing vintage radio troubleshooting. The isolation transformer works fine and appears to be well made.

Have a great day!

Works great

Now a staple component to my electronic desk.

Best,
Hans

Very nice

This is a real isolation transformer. Keeps me safe when doing my repairs.

Well designed product

300VA Isolation Transformer, 117VAC to 117VAC

300VA Isolation Transformer, 117VAC to 117VAC

Thanks for the 300VA Isolation Transformer, 117VAC to 117VAC. The shipping was fast look great and is heavy. transformer was a great price would buy from AC-DC PowerShack again.

Fast, efficient, and excellent price.
Thanks

Hello Roberto,

Thank you for your purchase and taking the time to leave a review. Have a great day!

Very loud hum

A Workbench Essential

I use this to isolate my Powerstat and Dimbulb on my workbench when testing electronic gear. 300 VA is all I need because of the Dimbulb limiter and it works as advertised.

Thank you for your review! We're thrilled to hear that our 300VA Isolation Transformer has become an essential tool on your workbench. We're glad it's working as advertised and meeting your needs.

Better than expected

Isolation transformer

Thank you for choosing our product and for sharing how you utilize the isolation transformer with the community. We hope to have the opportunity to serve you again in the future!

Assume it isolates, but dd not cure my noise problem

Regarding the hum, I will reach out to you to see if we can remedy the problem or provide a solution to your satisfaction.

We appreciate your feedback and are always looking for ways to improve our products.

Great product

Thank you for taking the time to leave a review for our 500VA Isolation Transformer. We are so glad to hear that it has been working as advertised and has greatly reduced the hum from your subwoofer.

If you have any further questions or concerns, please don't hesitate to reach out to us. We truly appreciate your support and hope you continue to enjoy our product.