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Tripp Lite IS250 Review (Isolation Transformer)

Rate this product:

  • 1. Waste of money for audio use

    Votes: 118 72.0%
  • 2. Not terrible (postman panther)

    Votes: 12 7.3%
  • 3. Fine (happy panther)

    Votes: 25 15.2%
  • 4. Great (golfing panther)

    Votes: 9 5.5%

  • Total voters
    164

Ingenieur

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Ok i give it a try! I assume the included pictures shows what you describe in the next sentences. Right?

but the picture shows a ground wire going to the secondary N?

So this connection is now shown in the picture is the first fault?
ok the picture shows both situations ?
On the top is youre preferred connection with N and PE connected and on the bottom is the faulty cases. (you assume i’m advocating for)

But the on the on the bottom the outlet is on the primary side?!
Then outlet PE would still be connected to PE? whey shuld it be energized.

I think we coming closer to outre misunderstanding!

I can’t answer your questions before i fully understand the scenario your depicting. Pleases help with this.

So this the first scenario?:
View attachment 199406
No it doesn't
The load served by the ungrounded sec is.

It is 1 system
An ungrounded isolation transformer servicing a grounded one, like in an amp to derive bipolar V DC.
The isolation transformer line is ground faulted (pinched, not severed, as is usually the case).
 

Ingenieur

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What scenario your talking about... it kind of matters.

what scenarios now?


I remember something like your not a real engineer and you only have google knowledge
Sorry i miss understand this as an persona personal attack.


what scenarios?!

If there is no return part. no current will flow.
no (high) current lowering trough a person is generally considered a good thing?

e02e5ffb5f980cd8262cf7f0ae00a4a9_press-x-to-doubt-memes-memesuper-la-noire-doubt-meme_419-238.jpg




lets keep it simple.
In this picture:
images

The higher "R" the lower "It" on Output1. we agree on this one?

In this picture:
index.php

The higher Risol the lower Ut.
If i ever said something else it was a mistake

Pleases link me to and i will edit it and make that i found this mistake tahnks to You're? help.


You're saying in the picture about Rk is in parallel with Risol?
(took me a moment to realize youre using // as || if you men in parallel)

Because i don’t see it! maybe i wrong. happens some time. can you help me see it.
To me it loos like this:
View attachment 199397
Can you show me how it looks to you?
You said current did not flow.
Then said it did.
It is the scenario YOU posted! Not mine.

Are you a credentialed EE? From your understanding it does not seem likely.
Not an attack, but an observation your can easily clarify.

I already said that, the higher the R, the lower the current. I corrected you when you said the exact opposite:
You: the lower Risol the lower Ut
My response "The higher Risol the lower Ut."

Textbooks use //
But you continuously correcting and mocking me about inconsequential semantics will end this conversation.

I already outlined the fault current path.
I'm done because you do not understand the basics.

NEC
NESC
UL
basic safety practice.
 
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Ingenieur

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What scenario your talking about... it kind of matters.

what scenarios now?


I remember something like your not a real engineer and you only have google knowledge
Sorry i miss understand this as an persona personal attack.


what scenarios?!

If there is no return part. no current will flow.
no (high) current lowering trough a person is generally considered a good thing?

e02e5ffb5f980cd8262cf7f0ae00a4a9_press-x-to-doubt-memes-memesuper-la-noire-doubt-meme_419-238.jpg




lets keep it simple.
In this picture:
images

The higher "R" the lower "It" on Output1. we agree on this one?

In this picture:
index.php

The higher Risol the lower Ut.
If i ever said something else it was a mistake

Pleases link me to and i will edit it and make that i found this mistake tahnks to You're? help.


You're saying in the picture about Rk is in parallel with Risol?
(took me a moment to realize youre using // as || if you men in parallel)

Because i don’t see it! maybe i wrong. happens some time. can you help me see it.
To me it loos like this:
View attachment 199397
Can you show me how it looks to you?
Consider this
E47A87BE-7839-412D-8B22-50676AB3155C.jpeg


Then factor this in
2A49622D-B6D8-4D15-8478-773699C06248.gif


When combined
F3548BBF-A8CF-49D5-B99F-11A0CD36260E.jpeg


The results
0ACC97E6-5335-4DA4-A892-04266C33D771.png

9CF849BA-CF91-466A-9366-641D221B8A00.jpeg




A5BCC030-E473-4A54-B7DC-52D1F470A0D4.gif

Lol
:D
 
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Lambda

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No it doesn't
Is an replay to:"assume the included pictures shows what you describe in the next sentences."

If you don't want to type: "No, the picture did not show what i’m describing in this post"
You can also select the part your referring to and replay to it direly like i did. so it is clear.

if the picture is not showing what your talking about. Why not?
Would help a lot ;)

The load served by the ungrounded sec is.
is what?
with your first sentence can assume it is an direct repay to my first questin in my quoted post. but this?
its not an answer to my second question?

It is 1 system
Again i have to guess to what your replaying and what "it" is.


An ungrounded isolation transformer servicing a grounded one, like in an amp to derive bipolar V DC.
The isolation transformer line is ground faulted (pinched, not severed, as is usually the case).
so your schematics is supposed to show an underground isolation transformer.
The isolation transformer as a fault. one of its lines is "shorted" to PE ground.
Connected to it is another transformer.
Let me redraw this for you:
1649793587448.png
 

Lambda

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You said current did not flow.
Context matters.
Where exactly did i said this to what.

Then said it did.
Where exactly did i said this to what?
maybe i was mistaking maybe i was talking about an different cases/ scenario.

It is the scenario YOU posted! Not mine.
What? i posted a lot of different scenario by now... I though i can uses simplified schematic "from google" and we can focus on the essentlais.
But it seams to have said tracked a lot....
So i simplified even more:
images


I already said that, the higher the R, the lower the current. I corrected you when you said the exact opposite:
You: the lower Risol the lower Ut
My response "The higher Risol the lower Ut."
Well if is said so i was wrong.
You are right.

!don’t know if this is what you want to hear.
i meant to say: "The higher Risol the lower Ut."

Can you point me to it? i want to mark it as fault and add the correction.
I don’t "delete" it but i want to add that this was a mistake.
I don't know if you believe me or if you care. but i did not meant to say so. Sorry.

so now it is a 3 pases system? cant we first make sure we talke abut the same basic schematic?!
we go into more special case and try to consider al the parasitic. simple first. then if we know we are talking abut the same ting. we can go more in detiels and special ceases.
 
OP
amirm

amirm

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You two are costing me a fortune in server costs to maintain those images. :) I suggest each of you make a summary post of your position and call it done after that.
 

Lambda

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I intentionally try to keep them small and use the same picture that is alley on the server or just quote the post.
but if you say so:

My cases is simple.
If the transformer secondary is isolated R is closes to infinite.
If then faulty equipment gets connected and i some how touch Out1 or Out2 nothing happens because R is so big taht almost no current can flow.
On the other hand
If the secondary is grounded R is is close to zero
If then faulty equipment gets connected and i some how touch Out1 i will get a shock an current is only limited by Rperson.

This is why the first cases is saver.
or to re use the pictures already on the server:
or an external video explaining it in 2 minutes:
 

Ingenieur

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Bonding the neutral is safer. Period
A floating neutral without additional expensive protection is dangerous.
Using a 'not a relay' although the mfg. calls them a 'relay adds complication, maintenance, risk and 0 benefit in a home appliance. It's actually dangerous and negligent. That is why it is not done.
NEC
NESC
NEMA
UL
etc.

In my sketch the fault will destroy both xfmrs (which apparently is not a thing lol) and possibly the load since phase has been inverted.

This has been determined by engineers over decades and not internet experts.
Thank God.

In terms of grounding, this means that the secondary output MUST be grounded, since it is another isolated part of the circuit. Any wiring failure downstream from the transformer must have a way to re-enter the circuit briefly in order to trip that circuit protection device. As with any supply, it is the Neutral wire which is bonded to ground, and this will happen just after the output of the transformer.

'Kirchhoff'
Are you saying the body Rk sees the entire fault current? It's in series?
Between all the snark

Quote:
you can say current an resistance btw.
But no fault current is Not divided between the person (Rk) and the isolation (Risol) resistance.
they are in Series! current I will not divide if in series... (really! Lol)
Maybe you shuld go back to the basic and look at kirchosf current law.


Even in YOUR sketch the L fault I is in //!
You can't make this stuff up.
The I 'divides', (which again is not a thing, current dividers do not exist), Risol // Rk, no matter how you slice it the fault I is shared (it is the ONLY source for current).
6FFEAE16-3E03-4E85-A46A-535D9459F6A8.png
9FCEFF3F-AFA4-4B74-A605-EA7AA51E78F2.jpeg



Duke W. Schamel, P.E., LEED AP, Electrical Service Solutions, Inc.​

After a national arc-flash hazard analysis project was performed at eight recently constructed parts distribution warehouse sites for a Global 100 company as part of an OSHA Voluntary Protection Program (VPP), management found the results to be somewhat shocking.

During the data gathering process, Electrical Service Solutions, Inc., discovered more than 35 violations of the National Electrical Code (NEC) involving improper bonding and grounding of transformers. Violations ranged from system bonding jumpers that were missing, undersized, improperly terminated, and installed in two locations to grounding electrode conductors that were either missing, undersized, improperly terminated to the electrode, and/or connected to the separately derived system in a location other than where the system bonding jumper was connected. These findings reiterate the fact that a significant amount of confusion still remains in the industry on the topic of bonding and grounding of transformers. Let’s take a closer look at the areas where most of the misconceptions arise.

The effective ground-fault current path​

To understand the concept of bonding and grounding for safety, the installer must know that for normal load current, short circuit current, or ground-fault current to flow, there must be a continuous circuit or path — and a difference of potential. The 2011 NEC defines the effective ground-fault current path as “an intentionally constructed, low-impedance electrically conductive path designed and intended to carry current under ground-fault conditions from the point of a ground fault on a wiring system to the electrical supply source and that facilitates the operation of the overcurrent protective device or ground-fault detectors on high-impedance grounded systems.” An effective ground-fault current path is an essential part of the overcurrent protection system.



In summary: folks, do NOT disconnect your N from G. Under any residential circumstance. Period.
A fault will reverse polarity, elevate the other G and N, likely damage equipment, cause arcing and possible fire.
And worse, injury or death.
 
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Ingenieur

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You two are costing me a fortune in server costs to maintain those images. :) I suggest each of you make a summary post of your position and call it done after that.
Just donated some $

After deducting the 'aggravation penalty' how much is left over for wasting server space trying to show something 99% already know, and even more do not care about.
:D

Yours truly,
"j"
 

C. Cook

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Funny. I have one of these and it's not currently in use. But at our old place, storms and general utility incompetence caused a whole lot of power surges (ruined one of my Hypex NC502MP amps for ex.) so I got this isolation transformer and used it in my main system for a while. Seemed to work in that regard. I also had it far away from the system, but plugged into the same outlet as one or two components (which were rarely used, DVD player, etc.) and never noticed any negative effects. I will say the motherf*!ker is one heavy little box!
 

JP

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Consider this scenario.
Ungrounded XFMR (lol)
The sec L goes to G/frame.
What happens to the equipment xfmr plugged in?
What happens if there are other receptacles on the circuit?
Would the CB trip?

If it were bonded would the fault I go thru the equipment xfmr or back to the source xfmr? Would the CB trip?

Sorry for the non-Google picture
View attachment 199233

Screen Shot 2022-04-12 at 8.44.03 PM.png
 

Ingenieur

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Hilarious!
05DB9E87-5FC8-4AC6-867F-AB3BEFB542F9.gif


I'm in a good mood, solved a 'real work' problem I had 6-8 hours into.
3 phase fault symmetrical components
No problem
Auto xfmr, breeze
NGR system, piece of cake

575:480 3 phase
But a NGR system feeding an AT
tougher, no magnetic isolation.
I finally solved it and confirmed it with a SC program. Another guy looked at it and agreed with the results.
I needed to determine the GF relay setting.
 
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Ingenieur

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You realize where i come from i can reverse the plug and it changes nothing.
Maybe this is your misunderstanding?
Changing N and L changes nothing!
Halve Europe is doing it all the time.


How? G is still connected to PE so it can’t get elevated
Folks, draw your own conclusions,
It is dangerous and not advised unless required by special use application with additional protective relaying.
NEC
NESC
UL
NEMA
PE's
100 years of development
et al

Or a non-engineer internet guy.
Here's the rub, it's dangerous AND won't help.

A ground-fault current path for a grounded separately derived system/transformer that doesn’t meet these criteria becomes a silent and often lethal source of electrical shock when a ground fault occurs. If an effective ground-fault current path isn’t established and a ground-fault occurs on the derived ungrounded circuit conductors of a transformer, ground-fault current will not flow; therefore, the operation of the overcurrent protection device in the ground-fault current path won’t be initiated. Electrical raceways, enclosures, and equipment will become energized with dangerous energy, continually searching for a path back to its source. When a human body completes the ground-fault current path, it results in electrical shock or electrocution. Unlike obvious indications of faulty wiring of branch or feeder circuits, defective high-impedance ground-fault current paths are difficult to detect, because these circuits are predominantly called upon when a ground fault occurs.
 

Ingenieur

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Funny. I have one of these and it's not currently in use. But at our old place, storms and general utility incompetence caused a whole lot of power surges (ruined one of my Hypex NC502MP amps for ex.) so I got this isolation transformer and used it in my main system for a while. Seemed to work in that regard. I also had it far away from the system, but plugged into the same outlet as one or two components (which were rarely used, DVD player, etc.) and never noticed any negative effects. I will say the motherf*!ker is one heavy little box!
It will attenuate line side/primary surges with its impedance.

When I improved my service ground and installed a surge suppressor it seemed to tame the occasional voltage dip.
eg, dryer on, wife cooking, etc. and the heat pump kicked on you would notice it, not bad, but noticeable at times.
No more? Go figure?
 

Lambda

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It is dangerous and not advised unless required by special use application with additional protective relaying.
And some how you failed to show us a Simplified schematic of in how and in what case it would be unsafe.
A transformer and 2 or 3 resists you can draw this to make it clear.
Maybe draw a current loop to make it super clear.

If for some reason you don’t have the software to do so i can do it for you if you give me a hand drawing and explanation.
Also here is a free and easy online tool. https://www.falstad.com/circuit/circuitjs.html


In order to ensure protection, there must be no electrical connection between the secondary side and earth potential or the protective conductor or other conductors on the primary side during operation. Only then will there be no current flow when touching one of the lines on the secondary side. If both lines of the secondary side are touched, you get the maximum possible electric shock. If the secondary side is grounded, the protective effect is lost. The transformer core can be grounded.


btw pma is using this kind of transformer. and it is also called "safety transformer" why/how would this become less save if PE device is connected Mains PE
PE in the device is always Isolated from N the same way it is isolated from L

 
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Ingenieur

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And some how you failed to show us a Simplified schematic of in how and in what case it would be unsafe.
A transformer and 2 or 3 resists yo can draw this to make it clear...




btw pma is using this kind of transformer. and it is also called "safety transformer" why/how would this become less save if PE device is connected Mains PE
PE in the device is always Isolated from N the same way it is isolated from L

That's nice
Thank you
I showed you, I drew a sketch, I explained how the stuff you posted works. I gave you articles, you know the old saying: you can lead a horse to water..,,
I'm done.

To all the others, do so at your own (and those around you's risk).
It is Code for a reason.
Safety

That transformer is only 250 VA, not UL listed and has additional internal protection and is $$$.
And provides no benefit.
Lowering line noise does not translate to lower system noise.
Amiir has shown that many times.

That device is made for 'special use', exterior construction where a ground is not derived. Outside, flexible cable, tools.
Not your home.


Here's the one for buildings.
 
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Lambda

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That transformer is only 250 VA, not UL listed and has additional internal protection and is $$$.
It has only isolation temperature protection and a overcurrent fuse, nothing fancy


Lowering line noise does not translate to lower system noise.
This was never up for debate... but very typical to shift the topic if you are proven wrong.

That transformer is only 250 VA, not UL listed and has additional internal protection and is $$$.
Eell yes its product for the European market... but you think only UL listing the true standards and only American safty Code is real code?

Maybe have a look at this product
And at UL File # E211544.

It is even UL listen save and leagl in the US.

Outside, flexible cable, tools.
Not your home.
So it is Save outside with potentially wet ground but not at home... makes perfect sense to me.

Sure.
You can’t draw a schematic showing how it is unsaved.
you keep quoting "code" but out of context saying it is "not up to code" but here "UL File # E211544." proofes it can be legal.
 

Ingenieur

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It has only isolation temperature protection and a overcurrent fuse, nothing fancy



This was never up for debate... but very typical to shift the topic if you are proven wrong.


Eell yes its product for the European market... but you think only UL listing the true standards and only American safty Code is real code?

Maybe have a look at this product
And at UL File # E211544.

It is even UL listen save and leagl in the US.


So it is Save outside with potentially wet ground but not at home... makes perfect sense to me.

Sure.
You can’t draw a schematic showing how it is unsaved.
you keep quoting "code" but out of context saying it is "not up to code" but here "UL File # E211544." proofes it can be legal.
That may be even more dangerous the 115:115 is bonded on both sides. Bonding the N is safer.
That is why it is standard practice. Do what you like but I am advising others not to cut the N to your transformers.
Dangerous and no benefit.

The device is Certified, not Listed.
It does not meet Code and safety standards.
 
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