Process liquid piping/tubing inside electrical junction box??!!

[Tip DS]

Everything in me says it's NOT ok, but I'm not finding the prohibiting code I'm looking for.

I'm being asked to design a junction panel where 277VAC is brought into a panel to power heat trace lines on some pipes and tubes. Ok, no problem. Thing is, the customer wants the pipes and tubes INSIDE the junction box. Obviously, I can make the argument about this configuration being unsafe, but the discussion is much simplified if I can point to mandatory code that says it is impermissible. Can anyone quote such code & provide the authoritative reference?

 

[Joe.B]

I would recommend that you say something like this:

Sure no problem, I can do that. Just provide me with a junction box that is listed for that purpose.
Oh, you haven't found the box yet? Okay no problem, I'll just add a note for the contractor to find and use a listed box.
What if they can't find a listed box?
Not my problem, you asked me to design it, not build it.

Electric Code citation? 110.3

 

[TwoBlocked]

I am thinking I have seen this sort of thing for heating natural gas samples as the pressure is reduced before analyzing it for ... moisture? But I would call this a control panel, not a junction panel (is that a proper term?) or a junction box.

 

[petersonra]

It is not a junction box. It is an instrument enclosure.

There is no general prohibition on putting such things in a box. It is common place.

 

[Tip DS]

It is not a junction box. It is an instrument enclosure.

There is no general prohibition on putting such things in a box. It is common place.

I may be misunderstanding your meaning, but there are all kinds of prohibitions on having explosive gases in a panel that's not specially designed and rated for such use.
In my scenario, I don't know if the process fluid is inherently Hazardous, but I'm led to understand it is conductive. I don't believe it is safe to have it run in an enclosure with 480VAC.

 

[petersonra]

I may be misunderstanding your meaning, but there are all kinds of prohibitions on having explosive gases in a panel that's not specially designed and rated for such use.
In my scenario, I don't know if the process fluid is inherently Hazardous, but I'm led to understand it is conductive. I don't believe it is safe to have it run in an enclosure with 480VAC.

I said there is no general prohibition on such things. That does not mean that every possible option would be a good idea.

Water is conductive. Would you have an issue with putting a sample valve in a box for water sampling?

 

[Tip DS]

I said there is no general prohibition on such things. That does not mean that every possible option would be a good idea.

Water is conductive. Would you have an issue with putting a sample valve in a box for water sampling?

I would have an issue with placing conductive liquids inside an enclosure where dangerous voltage was present, yes. Realistically, I see no reason to bring a liquid into an Electrical enclosure, when most sampling and measuring devices can be placed in the process stream, away from other electrical or electronic devices.

 

[TwoBlocked]

I would have an issue with placing conductive liquids inside an enclosure where dangerous voltage was present, yes. Realistically, I see no reason to bring a liquid into an Electrical enclosure, when most sampling and measuring devices can be placed in the process stream, away from other electrical or electronic devices.

If it is an area classified as hazardous, then the NEC articles for that class and division must be followed.

 

[TwoBlocked]

And if the concern is it being a wet location, there are NEC articles for that, too.

 

[kwired]

I may be misunderstanding your meaning, but there are all kinds of prohibitions on having explosive gases in a panel that's not specially designed and rated for such use.
In my scenario, I don't know if the process fluid is inherently Hazardous, but I'm led to understand it is conductive. I don't believe it is safe to have it run in an enclosure with 480VAC.

Aren't said gases contained in their piping? Even running such piping right next to the electrical enclosure instead of in the enclosure would still present the same hazards if there is any. Gas that is contained within piping doesn't normally trigger hazardous location ratings, that is triggered when said gases are expected to possibly be present in the air during normal activity, like near dispensing/transfer areas where gas does escape when connecting or disconnecting piping and such.

It can be normal to have a pipe pass through an enclosure, particularly if what is in that enclosure is primarily there for interaction with that pipe line in some manner.

Not acceptable would be a pull or junction box that has no direct relation to the piping that also occupies the box.

One example that comes to mind though not exactly something from typical industrial though you may see something similar is a packaged spa control panel. Most them have a tube passing through them that houses the heater and maybe temperature probes or even a pressure switch to interact with the controls in said panel with the water from the spa passing through the piping. I see no reason some industrial process couldn't do something similar with a pipeline passing through some sort of control panel, though many larger scale processes is usually sensors and such strategically placed throughout the piping system and associated wiring ran back to a control panel.

A somewhat common thing often is an air pressure maybe even oil pressure switch located within an control enclosure though. Actual line may not really enter but should a diaphragm in said switch fail it may leak into the control enclosure

 

[retirede]

In my scenario, I don't know if the process fluid is inherently Hazardous, but I'm led to understand it is conductive. I don't believe it is safe to have it run in an enclosure with 480VAC.

It sounds like you don’t even have adequate information to make the necessary determinations, and thus want to use an ultra-conservative design approach. Then you want someone here to tell you that’s the correct thing to do.

I won’t be that someone.

 

[Tip DS]

I appreciate the earnest attempts to be helpful, as well as the comedic replies. I've already quashed the idea of running the fluid through the enclosure. There really was no benefit to it. Thanks again.

 

[petersonra]

I don't see how it is inherently unsafe or a code violation. But, if you make a design decision not to bring tubing inside the box, that is a design decision and is up to the designer to make

 

[kwired]

What is inside this "junction box" and does it have components that interact with the process tubing?

Is one thing to mostly just have wiring associated with that process tubing and any interacting devices in an enclosure vs placing such process tubing into some power distribution box or some other similar situation that has little to do (directly) with the process tubing.

 

[petersonra]

What is inside this "junction box" and does it have components that interact with the process tubing?

Is one thing to mostly just have wiring associated with that process tubing and any interacting devices in an enclosure vs placing such process tubing into some power distribution box or some other similar situation that has little to do (directly) with the process tubing.

Why would that matter?

 

[petersonra]

Why would that matter?

Maybe to make my question more clear. If it is not prohibited by the code, why would the exact instance of what was done matter?

 

[Charged]

Is a decorative light pole with irrigation line to hanging baskets a similar condition in terms of code? I believe that’s done quite often.

 

[packersparky]

I appreciate the earnest attempts to be helpful, as well as the comedic replies. I've already quashed the idea of running the fluid through the enclosure. There really was no benefit to it. Thanks again.

How would you bring power to an electric on-demand water heater? The power is in the same enclosure as the water piping.

 

[Joe.B]

How would you bring power to an electric on-demand water heater? The power is in the same enclosure as the water piping.

Listed device. If I were the OP, I'd tell them to find a listed device. If one doesn't exist, there's probably a reason why.