Pool pump circuit- why in conduit?

[doug18812]

Does anyone know the reason that NEC does not allow a pool pump circuit to be wired using direct buried cable? 680.21 (1) of NEC states that the circuit must be installed using rigid metal/ intermediate metal/rigid nonmetallic conduit or type MC cable only. Why do they specifically not allow UF cable, even though it is suitable for other outdoor circuits.

Thanks.

Doug

 

[websparky]

Re: Pool pump circuit- why in conduit?

Hi Doug,

All of the wiring methods allowed in this section are "listed" for use with pool motors. The ones not listed are not "listed" for the use.

I don't know why......but I would venture a guess that because of the life safety issues around swimming pools and alike, they want to be sure there is a minimum potential for ground faults and they really like to be sure of equipment bonding.

Hope this helps,
Dave

 

[bennie]

Re: Pool pump circuit- why in conduit?

The article appears to be focused on a commercial type pool. With the separate section for One Family dwellings, I assume a pool at a residence is a different situation.

According to 680.21(4) A cable assembly can be used.

 

[curt swartz]

Re: Pool pump circuit- why in conduit?

Bennie

680.21(A)(4) Allows any of the wiring methods recognized in Chapter 3 to be used in the interior of a one-family dwelling but as soon as you exit the building you must comply with 680.21(A)(1).

 

[bennie]

Re: Pool pump circuit- why in conduit?

I guess I am missing the part about exiting the building.

 

[curt swartz]

Re: Pool pump circuit- why in conduit?

I assumed that this circuit was going to be outside since he was asking about UF cable. If he wants to use UF cable for the interior wiring then that would be permitted.

 

[bennie]

Re: Pool pump circuit- why in conduit?

I am also missing the part that UF is excluded.

 

[bennie]

Re: Pool pump circuit- why in conduit?

Doug: The reason for metal conduit is to provide physical protection from damage. The section 680.21 is addressed to outdoor pump and filter units. These are pad mounted, often with no cover.

The supply to these pads can be in UF cable, there is no specific exclusion.

The pumps in a private home, are not exposed to damage like the ones outside.

 

[websparky]

Re: Pool pump circuit- why in conduit?

Hi Bennie,

In this case, it is not so much that it is excluded, but rather that it is not included in any of the lists of acceptable wiring methods in Article 680. Motors being one of them that is specific as to wiring methods.

Dave

 

[bennie]

Re: Pool pump circuit- why in conduit?

This is another poorly written section...The motor circuits only have to be in metal conduit where physical protection is required.

Ask yourself...What other reason is there?

 

[tom baker]

Re: Pool pump circuit- why in conduit?

Part of the reason why conduit is required is so an insulated equipment grounding conductor will be installed, to beter protect against corrosion. The equipment grounding conductor in UF is not insulated, it is covered.
There is a good review of article 680 in the recent NFPA NEC Digest.

 

[bennie]

Re: Pool pump circuit- why in conduit?

The equipment ground conductor can be bare if covered, and not in a conduit.

Why is the equipment ground conductor required to be insulated or covered copper?

[ July 14, 2003, 06:45 AM: Message edited by: bennie ]

 

[bennie]

Re: Pool pump circuit- why in conduit?

I have had individuals tell me they have learned a lot from me. I actually think they have learned more when trying to disprove some of my statements. Unfortunately, for me, they often succeed.

This topic is another one that has taken on a new spin from it's origin. I was in the trade when it originated. Swimming pools first appeared in the 1950's.

The Beverly Hillbillies call a swimming pool, a cement pond.

From day one the requirement for an insulated ground conductor was included in the section. The reason is the presence of chlorine. Clorine is a halogen element, and an oxidizing agent.

The copper is subject to a high rate of decomposition when mixed with clorine.

An underground conduit is defeating the purpose for protecting the conductors. A direct buried cable is much better. Pool water, in the conduit, will accelerate the oxidation.

The 1999 NEC, used the words "EMT is permitted for protection of conductors inside a building"

This wording was deleted in 2002, no reason for this action other than the assumption everyone knows the conduit is for protection of conductors.

[ July 14, 2003, 01:13 PM: Message edited by: bennie ]

 

[bennie]

Re: Pool pump circuit- why in conduit?

Tom: I haven't read the publication you mentioned. What are some of the highlights?

 

[bennie]

Re: Pool pump circuit- why in conduit?

I am sure everyone does not agree with my take on this subject.

I often read advice by recognized code experts, that the circuits for the pool equipment must be in conduit from the panel to the pumps.

I have been exchanging emails with a gentleman from the UL Labs, about this issue. He is involved in swimming pool technology. He agrees with all my statements. He also agrees that some editing is needed on the code section.

 

[renosteinke]

Re: Pool pump circuit- why in conduit?

Most aren't aware of it, but a swimming pool can move quite a bit with the seasons- especially if the pool is emptied for the winter (the pool will actually "float" in the ground). Ditto for flooding.
I'd like there to be conduit, so new wire can be pulled later. Add some age and chlorine, and UF isn't all that flexible.

 

[bennie]

Re: Pool pump circuit- why in conduit?

The pump wiring has nothing to do with the instability of the pool. Many cases the pumps and filter are quite remote.

 

[mikeames]

Re: Pool pump circuit- why in conduit?

This is interesting. This topic came up today, and I had the same concerns. If you get more info on this beennie please post. I asked why conduit from panel to pump and no one could explain.

 

[bennie]

Re: Pool pump circuit- why in conduit?

Mike: You do not have to run conduit from the panel to the pumps. The circuits above ground, should be protected by conduit, just like any other system. There is no special magic in the conduit for pumps, that make it safer.

 

[bennie]

Re: Pool pump circuit- why in conduit?

I should add this disclaimer...Many in the trade interpret 680.21 to mean the entire circuits for the pumps, must be in conduit.

Read the part...Other wiring material shall be permitted in specific locations. The only condition is, the ground wire must be covered.

Direct burial is the other wiring method.

Check with the local inspector, and listen to his take on this. Let me know the outcome.