Propane station pump service

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LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Well, I was called to look at a job I haven't done before. A contractor called me to price running power to a pair of 10-HP pumps in an industrial park. The motors can be wired for 480v, with a rated current of approximately 12.5a, which obviously reduces conductor sizing, but possibly increases equipment cost.

The basic job includes coordinating with the POCO to bring 480v 3ph to a service panel, possibly involving extend their primary to new transformers, but they may opt to run secondaries to to the relatively small load. I don't yet know the secondary voltage at the last transformer bank, a couple of hundred feet away.

From the service panel location, I have about 75 feet of parking-lot asphalt to the nearest of the four big tanks on piers, where I have the option of running above ground about 50' to the two tank control switches, and from each about 25' to the two motors. I'm thinking two conduits from the panel, rather than one.

My questions have more to with the need for explosion-proof equipment and seal-offs: 1. Is rigid steel the best, easiest, or only option? 2. Does each end of each conduit run require sealing? 3. What about flexible connections to the motor compartments? 4. Do I request 480/277 for possible site-lighting?

Anything you can tell me or point me to would be greatly appreciated!
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
....My questions have more to with the need for explosion-proof equipment and seal-offs:

Anything you can tell me or point me to would be greatly appreciated!
My experience around classified locations is limited to hooking up gas pumps on hay farms but here is my take..

1. Is rigid steel the best, easiest, or only option? It's your best and easiest option inside the classified area.

2. Does each end of each conduit run require sealing? Yes

3. What about flexible connections to the motor compartments? Nope. It wa RMC all the way every time I did it. Someone will correct me if I'm wrong.

4. Do I request 480/277 for possible site-lighting? I don't know.
 

brantmacga

Señor Member
Location
Georgia
Occupation
Former Child
Propane station pump service

I think the last time I did any class I work, we were under the 2008 NEC, so it’s been awhile....

But take a look at article 514 for your class I boundaries, and then back at 501 for wiring methods. These tanks should be considered Class I Div II; someone please correct me if I’m wrong.

You do need seals at both ends; see 501.15(B).

Flexible connections are allowed; 501.10(B)(2).

You can use PVC for portions of the underground work; see 514.8 exception no. 2.

Also don’t forget the emergency shut-offs; 514.11.

If you’re getting 480/277 for the motors, may as well use it for the lights. No need to buy a transformer if you don’t have to.

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kwired

Electron manager
Location
NE Nebraska
My experience around classified locations is limited to hooking up gas pumps on hay farms but here is my take..

1. Is rigid steel the best, easiest, or only option? It's your best and easiest option inside the classified area.

2. Does each end of each conduit run require sealing? Yes

3. What about flexible connections to the motor compartments? Nope. It wa RMC all the way every time I did it. Someone will correct me if I'm wrong.

4. Do I request 480/277 for possible site-lighting? I don't know.

General rule for application like you had is to not use flexible connections whenever possible, but there is flexible connectors (in various lengths) for such applications, they aren't cheap either. https://www.grainger.com/product/10R010?cm_mmc=PPC:+Google+PLA&s_kwcid=AL!2966!3!281733297812!!!g!470555235082!&ef_id=VI7hFgAABIgqtTQY:20181008134010:s&gclid=Cj0KCQjwgOzdBRDlARIsAJ6_HNkekLrR34EcV_PSOCbqLyDpNWIkrfzglBW3OfDv2mgESqofksoAHKsaAqIVEALw_wcB
 

brantmacga

Señor Member
Location
Georgia
Occupation
Former Child
General rule for application like you had is to not use flexible connections whenever possible, but there is flexible connectors (in various lengths) for such applications, they aren't cheap either. https://www.grainger.com/product/10R010?cm_mmc=PPC:+Google+PLA&s_kwcid=AL!2966!3!281733297812!!!g!470555235082!&ef_id=VI7hFgAABIgqtTQY:20181008134010:s&gclid=Cj0KCQjwgOzdBRDlARIsAJ6_HNkekLrR34EcV_PSOCbqLyDpNWIkrfzglBW3OfDv2mgESqofksoAHKsaAqIVEALw_wcB

From 501.10(B)(2)

(2) Flexible Connections. Where provision must be made for flexibility, one or more of the following shall be permitted:
(1) Listed flexible metal fittings.
(2) Flexible metal conduit with listed fittings.
(3) Interlocked armor Type MC cable with listed fittings.
(4) Liquidtight flexible metal conduit with listed fittings.
(5) Liquidtight flexible nonmetallic conduit with listed
fittings.
(6) Flexible cord listed for extra-hard usage and terminated
with listed fittings. A conductor for use as an equipment grounding conductor shall be included in the flexible cord.
(7) For elevator use, an identified elevator cable of Type EO, ETP, or ETT, shown under the “use” column in Table 400.4 for “hazardous (classified) locations” and termina‐ ted with listed fittings.
Informational Note: See 501.30(B) for grounding requirements where flexible conduit is used.


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kwired

Electron manager
Location
NE Nebraska
From 501.10(B)(2)




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(B) is for division 2 locations, (A)(1) for division 1 locations is a shorter list, and product I linked to is about only flexible fitting that is listed for division 1 locations.

Propane pump - I guess if in a fixed piping system and no routine piping connections are being changed in the vicinity you might have a class 2 location. If a tank filling station is in the pump vicinity you likely have division 1 location.
 

brantmacga

Señor Member
Location
Georgia
Occupation
Former Child
Propane pump - I guess if in a fixed piping system and no routine piping connections are being changed in the vicinity you might have a class 2 location. If a tank filling station is in the pump vicinity you likely have division 1 location.

I could be wrong but I think this tank would be class I Div II .... LP gas would normally be contained.


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victor.cherkashi

Senior Member
Location
NYC, NY
sorry for my ignorance, I don't have experience with hazardous areas. is it electrical trade legally responsible to classify hazardous areas based on NEC?

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kwired

Electron manager
Location
NE Nebraska
I could be wrong but I think this tank would be class I Div II .... LP gas would normally be contained.


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Well gasoline dispensers - though not quite the same thing, the idea is to contain the gas as well, but vapors do escape but they typically are a little more open in the transition method. A propane tank filling station you still leak a little gas when uncoupling a line, I don't know if that is enough to trigger class 1 in a certain zone or not. Exact coupling methods used may make some difference. That said the pump motor may not be within that zone if it is away from where said coupling is happening.

Sometimes they purge a tank by putting vapor into it, releasing pressure, putting more vapor into it.....some gas is released in this process.
 

brantmacga

Señor Member
Location
Georgia
Occupation
Former Child
A propane tank filling station you still leak a little gas when uncoupling a line, I don't know if that is enough to trigger class 1 in a certain zone or not.


From 500.5(B)(2)

A Class I, Division 2 location is a location:
(1) In which volatile flammable gases, flammable liquid– produced vapors, or combustible liquid–produced vapors are handled, processed, or used, but in which the liquids, vapors, or gases will normally be confined within closed containers or closed systems from which they can escape only in case of accidental rupture or breakdown of such containers or systems or in case of abnormal operation of equipment, or
(2) In which ignitible concentrations of flammable gases, flammable liquid–produced vapors, or combustible liquid–produced vapors are normally prevented by posi‐ tive mechanical ventilation and which might become hazardous through failure or abnormal operation of the ventilating equipment, or
(3) That is adjacent to a Class I, Division 1 location, and to which ignitible concentrations of flammable gases, flam‐ mable liquid–produced vapors, or combustible liquid– produced vapors above their flash points might occasion‐ ally be communicated unless such communication is prevented by adequate positive-pressure ventilation from a source of clean air and effective safeguards against ventilation failure are provided.



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kwired

Electron manager
Location
NE Nebraska
From 500.5(B)(2)

A Class I, Division 2 location is a location:
(1) In which volatile flammable gases, flammable liquid– produced vapors, or combustible liquid–produced vapors are handled, processed, or used, but in which the liquids, vapors, or gases will normally be confined within closed containers or closed systems from which they can escape only in case of accidental rupture or breakdown of such containers or systems or in case of abnormal operation of equipment, or
(2) In which ignitible concentrations of flammable gases, flammable liquid–produced vapors, or combustible liquid–produced vapors are normally prevented by posi‐ tive mechanical ventilation and which might become hazardous through failure or abnormal operation of the ventilating equipment, or
(3) That is adjacent to a Class I, Division 1 location, and to which ignitible concentrations of flammable gases, flam‐ mable liquid–produced vapors, or combustible liquid– produced vapors above their flash points might occasion‐ ally be communicated unless such communication is prevented by adequate positive-pressure ventilation from a source of clean air and effective safeguards against ventilation failure are provided.



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Doesn't exactly address the leakage that I addressed. If such leakage is considered normal and there is no ventilation to assure removal of such gases I think it is going to be deemed class 1. Now the pump may not be in the class 1 area or even in a classified area at all if it is away from the place where this leakage is expected to occur. Might be a switch for the pump in the class 1 location and proper wiring methods will apply to it.
 

nhee2

Senior Member
Location
NH
Is this application a motor fuel dispensing application? If not then 514 doesn't even apply. Personally I don't think table 514.3(B)(2) which is supposed to be for LNG/CNG/LPG fueling applications provides adequate guidance and standards like NFPA 52, 59A and 58 are more helpful.

NFPA 58 provides guidance for classifying LPG areas/equipment. I only have 2011 version, but generally the areas that are Division 1 are indoors, or outdoors within 5' of bleeds/drips/vents/drains, within 5' of a point of transfer. Otherwise it is likely Division 2.
 
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