Direct Bury Magnetic Flow Meter (mag meter) -- Code Section?

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lakee911

Senior Member
Location
Columbus, OH
I have an application where I need to direct bury a magnetic flow meter. The product allows direct bury if it's fully potted with a NEMA 6P rating. My rep says he's not familiar with the code but he hears that there is something about "direct bury of active components."

I've looked through my 2011 copy and I can't find anything. Anyone know of anything that might govern this install?

Thank you.
 

plumb bob

Member
I doubt you'll find anything in the NEC about a direct burial mag meter, either prohibiting it or allowing it. That would leave you only to consider the wiring method and whether it must remain accessable. Even if you use a compliant direct burial method of wiring, IMO any connections at the meter would need to remain accesable. Can you get a portion of the process pipe where the flow meter attatches to into an open bottom quazite box?
 

tom baker

First Chief Moderator
Staff member
I've installed a lot of mag meters, 3 in the last month, 4" 8" and 24" and ordered a 4th which will be direct bury. Its a pretty common practice. There is no need to access the connections to the sensor (flow tube) as they are sealed with SilGuard (silicon). And the connections to the sensor are very low voltage. The connections would be rated IP 66 and NEMA 6P. Make sure it works before you backfill....
No code violation at all.
 

lakee911

Senior Member
Location
Columbus, OH
Can you get a portion of the process pipe where the flow meter attatches to into an open bottom quazite box?

This thought occurred to me as well, but honestly there is nothing to do there. The connections are potted and made inaccessible with the full submersion kit.

It's going to be governed in part by manufacturer's instructions.
Good point. I'll ask my rep to reach out to the manufacturer.

I've installed a lot of mag meters, 3 in the last month, 4" 8" and 24" and ordered a 4th which will be direct bury. Its a pretty common practice. There is no need to access the connections to the sensor (flow tube) as they are sealed with SilGuard (silicon). And the connections to the sensor are very low voltage. The connections would be rated IP 66 and NEMA 6P. Make sure it works before you backfill....
No code violation at all.

Thanks, Tom. Do you do anything special when bringing conduits into the buried mag body? Since it's the low point, it's hard to arrange them to drain. I'd like to keep as much water out as possible.

Is that SilGuard the flexible silicon potting compound? I ran into one at a job site--Owner provided it for the Contractor--that was removable. It was for a mag in a vault. I don't know that I'd trust a flexible removable kind when buried. The kind I'm used to is a hard plastic non removable type.
 

tom baker

First Chief Moderator
Staff member
For sealing conduits I have used duct seal One mfg has an O ring and plastic sleeve to use to seal, But the European standard is to use cables and not conduit, even in direct buried. The preterminated Endress and Hauser have cables, I haven't done a direct bury of that meter yet. But I always seal the connections in the sensor head. Silguard is a two part silicon comes in two cans or a caulking tube. It cures perfectly clear and is possible to reenter, but its like digging thru vasoline.
 

lakee911

Senior Member
Location
Columbus, OH
But the European standard is to use cables and not conduit, even in direct buried.

Well, a lot of there stuff is IEC rated too ... I find better quality in Playskool. I prefer NEMA and other North American practices. :thumbsup:

Silguard is a two part silicon comes in two cans or a caulking tube. It cures perfectly clear and is possible to reenter, but its like digging thru vasoline.

I think that's probably the stuff that I had encountered before too.

I reached out to the manufacturer--Siemens is who I design around--and I'm waiting to hear back still.

Thanks!
 

tom baker

First Chief Moderator
Staff member
I agree a lot of the IEC stuff is not as robust as NEMA. The terminals are small and dainty. Not a lot of space. But the IEC practice is to not overengineer.
Siemens I have installed quite a few of their MagFlows. They have good tech support at 800-333-7421
 
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