Article 500.8 Equipment

[Dale001289]

I have a large, vendor supplied Control Panel, Nema 4X SS, mounted in Class I, Division 2 location. It contains 120VAC and 24VDC, has CB's, fuses, power supplies and switches, BUT, does not contain a Z-Purge. According to the vendor, it doesn't require one since all devices are 'rated' for the Area Classification.

Upon reviewing devices, most have sealed contacts however the power supplies are labeled, 'Class I, Zone 2' (per UL60079-15/CSA E60079-15)--nowhere does it mention 'Division 2'.

My question, will Zone 2 rated equipment suffice for Division 2 or is this a Code violation?

Thanks in advance.

 

[rbalex]

...
My question, will Zone 2 rated equipment suffice for Division 2 or is this a Code violation?
...

As a rule, Yes. See Section 501.5. Without actually seeing the other components, I can't tell if the overall assembly is proper or not. Division 2 is fairly generous with a lot of general purpose equipment as well. See Article 501, Part III beginning with Section 501.100

 

[Dale001289]

As a rule, Yes. See Section 501.5. Without actually seeing the other components, I can't tell if the overall assembly is proper or not. Division 2 is fairly generous with a lot of general purpose equipment as well. See Article 501, Part III beginning with Section 501.100

Bob, thanks for pointing this out. I believe the panel in question will be deemed suitable for CID2, without a purge. Curiously, 500.8(C) doesn't refer to 505.9(C)(1) - but 505.9(C)(1) mentions 500.8(C).

 

[Dale001289]

As a rule, Yes. See Section 501.5. Without actually seeing the other components, I can't tell if the overall assembly is proper or not. Division 2 is fairly generous with a lot of general purpose equipment as well. See Article 501, Part III beginning with Section 501.100

Bob, Currently we have a 40HP, squirrel cage inductionmotor, 3ph 460V, ODP (Open Drip Proof) installed in a Sump Pit – (Class I Division2 above grade/Class I, Division 1 below grade).
The motor is not Explosion Proof, it is rated, ‘ClassI Zone 1’ per the nameplate.
If I go by 500.125(A)(1), this motor fails to meet AreaClassification. However looking at 505.9(C )(1), I’m not 100% sure.

Can you comment

 

[rbalex]

Bob, thanks for pointing this out. I believe the panel in question will be deemed suitable for CID2, without a purge. Curiously, 500.8(C) doesn't refer to 505.9(C)(1) - but 505.9(C)(1) mentions 500.8(C).

Bob, Currently we have a 40HP, squirrel cage inductionmotor, 3ph 460V, ODP (Open Drip Proof) installed in a Sump Pit – (Class I Division2 above grade/Class I, Division 1 below grade).
The motor is not Explosion Proof, it is rated, ‘ClassI Zone 1’ per the nameplate.
If I go by 501.125(A)(1), this motor fails to meet AreaClassification. However looking at 505.9(C )(1), I’m not 100% sure.

Can you comment
[RBA Note: I corrected the Section 500 reference to 501.]

NEC "Division" Installations and IEC "Zone" Installations are two separate, self-consistent systems. NEC "Zones" is not entirely self-consistent.

As you have described it, since the location is classified by "Divisions", the motor is in violation. Period. If it were classified by Zones per Figure 514.3(B) and Table 514.3(B)(1) the motor would be in Zone 1. However, if it were consistently marked per IEC Zones it would probably still be in violation, since IEC would never mark an Open Drip Proof motor as suitable for Zone 1. In fact, it probably wouldn't be marked for Zone 2 either.

You have stumbled on one of the NEC inconsistencies. NEC "Zones" are an attempt to force-fit IEC "Zones" into a "Division" philosophy. They aren't consistent so NEVER use Article 505 to evaluate a "Division" classified location. I co-authored a paper about 20 years ago comparing NEC "Divisions" and IEC "Zones". Since the APEX Directive it's a bit dated, but still pretty accurate. I believe the Figure 514.3(B) and Table 514.3(B)(1) are in error and the pit should be Zone 0 as well as several other Zone 1 classified locations.

Basically IEC Zone 1 is often a "super" Division 2 as indicated in Figure 2 of the paper.

 

[Dale001289]

Thanks again Bob. I will note this to the Client.

 

[Dale001289]

NEC "Division" Installations and IEC "Zone" Installations are two separate, self-consistent systems. NEC "Zones" is not entirely self-consistent.

As you have described it, since the location is classified by "Divisions", the motor is in violation. Period. If it were classified by Zones per Figure 514.3(B) and Table 514.3(B)(1) the motor would be in Zone 1. However, if it were consistently marked per IEC Zones it would probably still be in violation, since IEC would never mark an Open Drip Proof motor as suitable for Zone 1. In fact, it probably wouldn't be marked for Zone 2 either.

You have stumbled on one of the NEC inconsistencies. NEC "Zones" are an attempt to force-fit IEC "Zones" into a "Division" philosophy. They aren't consistent so NEVER use Article 505 to evaluate a "Division" classified location. I co-authored a paper about 20 years ago comparing NEC "Divisions" and IEC "Zones". Since the APEX Directive it's a bit dated, but still pretty accurate. I believe the Figure 514.3(B) and Table 514.3(B)(1) are in error and the pit should be Zone 0 as well as several other Zone 1 classified locations.

Basically IEC Zone 1 is often a "super" Division 2 as indicated in Figure 2 of the paper.

Hi Again Bob,
Some of my colleagues are trying hard to convince me Zone 1 is exactly the same thing as Division 1. I skimmed through your paper and noted Zone 1 equipment is not always suited for Division 1 and may fall into Division 2 based on API/RP 500, which is one of our base standards on this Project.
I'm going to argue the said 'Zone 1' motor is in violation of our project specifications. Also going to make a case the sump is really a Zone 0 equivalent - not Zone 1.

Thanks again for all your help.

 

[rbalex]

Hi Again Bob,
Some of my colleagues are trying hard to convince me Zone 1 is exactly the same thing as Division 1. I skimmed through your paper and noted Zone 1 equipment is not always suited for Division 1 and may fall into Division 2 based on API/RP 500, which is one of our base standards on this Project.
I'm going to argue the said 'Zone 1' motor is in violation of our project specifications. Also going to make a case the sump is really a Zone 0 equivalent - not Zone 1.

Thanks again for all your help.

I would suggest rereading Section 501.5 carefully. Equipment marked for Zone 0, 1, or 2 is acceptable in Division 2; but only Zone equipment marked Zone 0 is suitable for Division 1. (Kinda like the paper says)

Compare that with Section 505.9(C)(1) for using Division rated equipment in Zones.

BTW, My coauthor, Joe Kuczka, represented NEMA on Code Making Panel 14 (CMP14) nearly 40 years. He had one of the longest tenures ever on any CMP. I didn't join the Panel until after the Paper. (2002 NEC) See the rest of my profile for more info.

 

[Dale001289]

Excellent! Thanks Bob


Sent from my iPhone using Tapatalk