External bonding on liquidtite in C1, D2 areas

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waynec said:
Is an external bond wire required on instrument installations in a Class 1 Division 2 location. 501.30 leads me to believe it is required.
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501.30(B) Types of Equipment Grounding Conductors. Flexible
metal conduit and liquidtight flexible metal conduit
shall include an equipment bonding jumper of the wire type
in compliance with 250.102.

Exception: In Class I, Division 2 locations, the bonding
jumper shall be permitted to be deleted where all of the
following conditions are met:
(1) Listed liquidtight flexible metal conduit 1.8 m (6 ft) or
less in length, with fittings listed for grounding, is used.
(2) Overcurrent protection in the circuit is limited to 10
amperes or less.
(3) The load is not a power utilization load.
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It appears that unless you meet the exceptions a wire type bonding jumper is required. I don't see that it is required to be external. It might be the only practical way to do it though.
 
petersonra said:
It appears that unless you meet the exceptions a wire type bonding jumper is required. I don't see that it is required to be external. It might be the only practical way to do it though.
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My next question what is a power utilization load. I look at it as anything that uses power. Without power the instrument will not work.
 
petersonra said:
It appears that unless you meet the exceptions a wire type bonding jumper is required. I don't see that it is required to be external. It might be the only practical way to do it though.
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What is considered a power utilization load? I consider a 24 volt instrument as a power utilization load. Your thoughts?
 
waynec said:
What is considered a power utilization load? I consider a 24 volt instrument as a power utilization load. Your thoughts?
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As absurd as it sounds, I think you might be right.

I suppose you could have a switch that actually did not use any power that could use this exception.

It seems kind of silly to make such an exception as there does not seem to be any good reason to do so.
 
petersonra said:
As absurd as it sounds, I think you might be right.

I suppose you could have a switch that actually did not use any power that could use this exception.

It seems kind of silly to make such an exception as there does not seem to be any good reason to do so.
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And you were doing so well. (Truthfully). Utilization is understood in terms of the load and not the controls equipment, so a switch wouldn't count.

Ever since ISA took over the IEC HAZLOC representation for the US (that's why various ANSI/ISA 12.xx.xx documents are cited all over the place in the NEC) many rules in Chapter 5 and elsewhere are accommodations to the Control Systems/Instrumentation field. Essentially, non-power utilization is intrinsically safe systems, nonincendive systems, power-limited and signaling Class 2 and 3 circuits installed under Articles 725 and 727, and various other telecommunications systems under Chapter 8. Other Chapter 7 installations may apply as well. Of course, they still have to meet Section 501.30(B) Exception.

BTW Utilization Equipment is a defined term in Chapter 100 and Section 501.135(B) references several Division 2 "power" utilization type equipment concepts. I realize Section 501.135 includes switches, circuit breakers, and fuses; such is the nature of NEC ambiguity. I would include most luminaires under Section 501.130 as power utilization equipment as well.
 
rbalex said:
And you were doing so well. (Truthfully). Utilization is understood in terms of the load and not the controls equipment, so a switch wouldn't count.

Ever since ISA took over the IEC HAZLOC representation for the US (that's why various ANSI/ISA 12.xx.xx documents are cited all over the place in the NEC) many rules in Chapter 5 and elsewhere are accommodations to the Control Systems/Instrumentation field. Essentially, non-power utilization is intrinsically safe systems, nonincendive systems, power-limited and signaling Class 2 and 3 circuits installed under Articles 725 and 727, and various other telecommunications systems under Chapter 8. Other Chapter 7 installations may apply as well. Of course, they still have to meet Section 501.30(B) Exception.

BTW Utilization Equipment is a defined term in Chapter 100 and Section 501.135(B) references several Division 2 "power" utilization type equipment concepts. I realize Section 501.135 includes switches, circuit breakers, and fuses; such is the nature of NEC ambiguity. I would include most luminaires under Section 501.130 as power utilization equipment as well.
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good point. so if you wanted to wire a switch this way you couldn't use this exception since it is not a load.
 
petersonra said:
good point. so if you wanted to wire a switch this way you couldn't use this exception since it is not a load.
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Whether a wire bond is necessary for a given FMC or LFMC depends on the nature of the circuit, the load being part of the overall evaluation. A switch may be used in a low power circuit in some of the examples I cited before so the Exception may apply. It's a case by case issue.
 
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