2 seal offs required?

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arits74

Senior Member
Location
dixie arkansas
Occupation
working owner electrician
a rigid conduit is ran from a panel in a farm shop to a pit in the ground for servicing vehicles,the pit does have motor oil piped in from a tank out side and also a pipe to remove the old oil to a tank out side,does the conduit have to have seal offs at each end or just where it turns up out of the slab under the panel?
 
mcclary's electrical

mcclary's electrical

Senior Member
Location
VA
arits74 said:
a rigid conduit is ran from a panel in a farm shop to a pit in the ground for servicing vehicles,the pit does have motor oil piped in from a tank out side and also a pipe to remove the old oil to a tank out side,does the conduit have to have seal offs at each end or just where it turns up out of the slab under the panel?
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WElcome to the forum,,,,the pit should be considered class 1 division 1
 
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jdsmith

Senior Member
Location
Ohio
arits74 said:
a rigid conduit is ran from a panel in a farm shop to a pit in the ground for servicing vehicles,the pit does have motor oil piped in from a tank out side and also a pipe to remove the old oil to a tank out side,does the conduit have to have seal offs at each end or just where it turns up out of the slab under the panel?
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What is the chance of getting gosoline, diesel fuel, or other flammable substances into the pit? Lubricating oil at low temperatures and pressures is not sufficient to justify classifying the area. Other fuels that are more volatile would cause the area to be classified.
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I'll be the "odd man". I believe based on '08 Art 511, it could be a classified area. It seems to fit 511.2 "Minor Repair Garage".
511.(3)(D)(3) should apply in my opioion and unless the pit is ventilated it will be a Class 1 Div 2.
Requirement for seals will depend on what the conduit feeds.
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Short answer I think would be a seal-off as you leave the pit as the ground you are entering is an un-classified area.
You mentioned a motor and, assuming there may be switching, you would need to address all those components as well.
I would think that it would be far simpler to provide air changes per 511.3(D)(3)
 
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arits74

Senior Member
Location
dixie arkansas
Occupation
working owner electrician
the conduit comes into the side of the pit which will be a pain to get a seal off on,i was hoping to only put a seal off at the opposite end of the pit,LOL
 
kwired

kwired

Electron manager
Location
NE Nebraska
arits74 said:
the conduit will supply 2 lights,2 receptacles,and a pump to take the old oil out side
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If all this equipment is in an article 500 area is that equipment rated for use in the area including the lights and the receptacles. As mentioned proper ventilation can de-classify the area.
 
kwired

kwired

Electron manager
Location
NE Nebraska
arits74 said:
i see there is no simple answer,LOL,i honestly believe the code is hard to interpret on purpose
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90.1(C) Intention.

This Code is not intended as a design specification or an instruction manual for untrained persons.
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You change the design on something and often the codes that apply will change also. Sometimes a simple design change can make a big change in installation cost because of all the requirements that may be attached to the design.
 
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pcorun

Member
Another question on interpreting 511.3(D)(3)

Another question on interpreting 511.3(D)(3)

As I have read this thread I have come across a discrepency between the Handbook and the black code book. The local inspector and I were discussing this very topic, a pit for large truck services. The client wants lights and outlets in the space. Inspector says that the pit is Class 1 Div 1 or div 2 if proper ventaliation is provided. However as I read this section in the handbook it clearly states that if the 1 CFM per Sq. Ft. is provided 12" from the floor of the pit, then the area shall be unclassified. Can you all help me understand if this is a true and accurate intrepretation?? If the pit is unclassified can standard fixtures, outlets, raceways, and boxes be installed in the pit??

Any help appreciated.
 
kwired

kwired

Electron manager
Location
NE Nebraska
pcorun said:
As I have read this thread I have come across a discrepency between the Handbook and the black code book. The local inspector and I were discussing this very topic, a pit for large truck services. The client wants lights and outlets in the space. Inspector says that the pit is Class 1 Div 1 or div 2 if proper ventaliation is provided. However as I read this section in the handbook it clearly states that if the 1 CFM per Sq. Ft. is provided 12" from the floor of the pit, then the area shall be unclassified. Can you all help me understand if this is a true and accurate intrepretation?? If the pit is unclassified can standard fixtures, outlets, raceways, and boxes be installed in the pit??

Any help appreciated.
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I think 511.3(D)(3) is pretty clear what the intent is without having to read the handbook or other references.

Another suggestion - this is an old thread, and you are basically starting a new discussion. You should probably open a new thread with your question.

Welcome to the forum.
 
LEO2854

LEO2854

Esteemed Member
Location
Ma
pcorun said:
As I have read this thread I have come across a discrepency between the Handbook and the black code book. The local inspector and I were discussing this very topic, a pit for large truck services. The client wants lights and outlets in the space. Inspector says that the pit is Class 1 Div 1 or div 2 if proper ventaliation is provided. However as I read this section in the handbook it clearly states that if the 1 CFM per Sq. Ft. is provided 12" from the floor of the pit, then the area shall be unclassified. Can you all help me understand if this is a true and accurate intrepretation?? If the pit is unclassified can standard fixtures, outlets, raceways, and boxes be installed in the pit??

Any help appreciated.
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Read 90.5(c) Explanatory Material in the hand book is not part of the code "BLACK" only what is in the soft bound book is the code.//Welcome to the forum.
 
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wireguy8169

Senior Member
Location
Southern Maine
It does not seem to be by the code a C1D1 location, I think unless it falls under (10) it wouldn't at least as far as I see. Does the conduit pass through any other areas that may be?

500.5 (B) (1) Class I, Division 1

FPN No. 1: This classification usually includes the following
locations:

(10) All other locations where ignitible concentrations of
flammable vapors or gases are likely to occur in the
course of normal operations

but as stated already if its ventilated then it would more than likely be unclassified if not C1D2
 
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