Recommended-Yea or Nay

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patpappas

Member
A manufacturers term "recommemded" doesn't say you have to but "we" think it is a good idea. When an installer has a different idea does that make the installation wrong for not following the remommendation, the equipment is connected, just differerntly. Rigid conduit connected to viberating equipment supported by trapeeze hangers vs. flexible conduit connections (manuacturers recommemdation).
 

growler

Senior Member
Location
Atlanta,GA
I agree that recommemded doesn't mean that it is required but is a manufacturer's suggestion.


But I also think that anyone that runs rigid conduit to a piece of equipment that will vibrate is not very smart. I think it is poor practice.

I think it was Ben Franklin that said common sense is not all that common.
 

kwired

Electron manager
Location
NE Nebraska
If the speed limit is 75, but there is a blizzard, heavy fog, heavy rain, or snow or ice on the roadway, it is generally recommended to drive slower, but usually not required either. I think some places they can ticket you for driving too fast for the conditions though. But there is no set law as to just what conditions dictate what speed either making this entirely the discretion of the officer issuing the citation:huh:

Kind of leaves your question unanswered doesn't it?
 

kwired

Electron manager
Location
NE Nebraska
I agree that recommemded doesn't mean that it is required but is a manufacturer's suggestion.


But I also think that anyone that runs rigid conduit to a piece of equipment that will vibrate is not very smart. I think it is poor practice.

I think it was Ben Franklin that said common sense is not all that common.

RMC will transfer that vibration to other things, but besides that it will likely last longer than most other rigid types of raceways.
 

jumper

Senior Member
I recently faced a scenario such as this.

Line reactors were wired as A1, A2, A3-load; B1, B2, B3-line.

I made the guys change them although the reactors would be fine wired that way.

The recommendations from the manufacturer were as such, plus I just did not like the oddity, required-no.
 

patpappas

Member
If the speed limit is 75, but there is a blizzard, heavy fog, heavy rain, or snow or ice on the roadway, it is generally recommended to drive slower, but usually not required either. I think some places they can ticket you for driving too fast for the conditions though. But there is no set law as to just what conditions dictate what speed either making this entirely the discretion of the officer issuing the citation:huh:

Kind of leaves your question unanswered doesn't it?

I had thought about the spped limit analogy too.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
I recently faced a scenario such as this.

Line reactors were wired as A1, A2, A3-load; B1, B2, B3-line.

I made the guys change them although the reactors would be fine wired that way.

The recommendations from the manufacturer were as such, plus I just did not like the oddity, required-no.

They had it right Jumper.
A=after line
B=before load
:p:angel::D
 

iwire

Moderator
Staff member
Location
Massachusetts
How about just going with the definition of recommended? :)


rec?om?mend
transitive verb \ˌre-kə-ˈmend\

Definition of RECOMMEND

1
a : to present as worthy of acceptance or trial <recommended the medicine>
b : to endorse as fit, worthy, or competent <recommends her for the position>

2
: entrust, commit <recommended his soul to God>

3
: to make acceptable <has other points to recommend it>

4
: advise <recommend that the matter be dropped>

Seems voluntary to me.
 

RICK NAPIER

Senior Member
Location
New Jersey
This information is also found in several years of these reports and in UL sponsered forums.

REPORT ON DISCUSSIONS
DURING UL MEETINGS WITH ELECTRICAL INSPECTORS AT THE 2007 IAEI SECTION MEETINGS

UL LISTING, CLASSIFICATION AND FIELD EVALUATION INFORMATION

Q.
Following manufacturer?s installation instructions. [FONT=IBJPFA+Arial,Arial][FONT=IBJPFA+Arial,Arial]AHJs are some times placed in a difficult position due to manufacturer?s installation instructions that are more stringent than minimum NEC? requirements. For a hot tub rated 50A, the installation instructions indicate that all supply conductors should be 6 AWG. The installer used an NM cable with a 10 AWG equipment grounding conductor. This would be a code-compliant installation, but had to be rejected by the AHJ because the instructions were not followed. [/FONT][/FONT]
A.
Installation instructions provided with UL Listed products are reviewed as part of the Listing investigation. Manufacturer?s recommendations that are part of the installation instructions should be followed in order to comply with NEC
? Section 110.3(B). The AHJ should expect all installation instructions provided with UL Listed equipment to be available for review at the time of inspection.
If an AHJ believes that the manufacturer?s recommendations in the installation instructions exceed what is necessary for a safe installation, then NEC? Section 90.4 gives the AHJ the ability to approve the installation.
If an AHJ believes that a product?s installation instructions conflict with the NEC? or other Model Code, we would encourage you to please file a Field Report using our online report form at:
[FONT=IBJPCP+Arial,Bold,Arial][FONT=IBJPCP+Arial,Bold,Arial][/FONT][/FONT]https://www.ul.com/regulators/ahjprod.cfm, or contact a Regulatory Services staff member at [FONT=IBJPCP+Arial,Bold,Arial][FONT=IBJPCP+Arial,Bold,Arial]1-800-595-9844 [/FONT][/FONT]or by email at:
[FONT=IBJPCP+Arial,Bold,Arial][FONT=IBJPCP+Arial,Bold,Arial]ULRegulatoryServices@us.ul.com [/FONT][/FONT].

 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
This information is also found in several years of these reports and in UL sponsered forums.

REPORT ON DISCUSSIONS
DURING UL MEETINGS WITH ELECTRICAL INSPECTORS AT THE 2007 IAEI SECTION MEETINGS

UL LISTING, CLASSIFICATION AND FIELD EVALUATION INFORMATION

Q.
Following manufacturer?s installation instructions. AHJs are some times placed in a difficult position due to manufacturer?s installation instructions that are more stringent than minimum NEC? requirements. For a hot tub rated 50A, the installation instructions indicate that all supply conductors should be 6 AWG. The installer used an NM cable with a 10 AWG equipment grounding conductor. This would be a code-compliant installation, but had to be rejected by the AHJ because the instructions were not followed.

A.
Installation instructions provided with UL Listed products are reviewed as part of the Listing investigation. Manufacturer?s recommendations that are part of the installation instructions should be followed in order to comply with NEC
? Section 110.3(B). The AHJ should expect all installation instructions provided with UL Listed equipment to be available for review at the time of inspection.
If an AHJ believes that the manufacturer?s recommendations in the installation instructions exceed what is necessary for a safe installation, then NEC? Section 90.4 gives the AHJ the ability to approve the installation.
If an AHJ believes that a product?s installation instructions conflict with the NEC? or other Model Code, we would encourage you to please file a Field Report using our online report form at:
https://www.ul.com/regulators/ahjprod.cfm, or contact a Regulatory Services staff member at 1-800-595-9844 or by email at:
ULRegulatoryServices@us.ul.com .


That certainly makes things clear. No question at all now.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
I am a fan of following the manufacturer's recommendations. It just makes everything simpler in the long run.

It still leaves some room for doubt as to "manufacturer's recommendations" versus "manufacturer's requirements". Recommendations which are part of installation instructions have the greatest weight, but I do not see them as being mandatory or even presumed requirements. I think that the
The manufacturer may recommend that you always purchase two units so that you have a spare, but I cannot see that as a safety-related or Code issue. :)

The quote refers primarily to "instructions" which are absolute rather than "recommendations" even though the latter word is used.

If the hot tub manufacturer says that all conductors "shall" be 6AWG it is different from saying that they "should" be 6AWG, but I don't think the writers of the instructions always understand the distinction.
Bottom line is that it is the AHJ's call, and unless there is a good reason for doing it differently in a specific situation, the recommendations are the gold standard.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
When I was in the field, I was one of those who took the work "recommendation" as a suggestion, not a rule. Now that I work for a manufacturer, I have a totally different take on this. I see that 'recommendations' are not just made up out of whole cloth to annoy users, they usually stem from the concentration of experiences in the field trouble calls, as in;

"9 out of 10 times when someone uses rigid conduit going to this vibrating equipment, the conductor insulation wears through and we get a trouble call. Add a recommendation to the manual to use flexible conduit."
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
"9 out of 10 times when someone uses rigid conduit going to this vibrating equipment, the conductor insulation wears through and we get a trouble call. Add a recommendation to the manual to use flexible conduit."

Words of wisdom to be sure, and not to follow that particular kind of recommendation would be foolish. But does that make it a Code requirement?
A similar argument came up with cable which included not a recommendation but a specific directive not to relabel the conductors with colored tape. That was never settled to everyone's satisfaction either. :)
 
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