NEC PVC SEC fastener spacing

Hello All,

Can someone point me to where in the NEC (2017) it states the proper fastener spacing for a service entrance cable running through PVC conduit?

I’ve found the following:
Ok to use PVC…
230.50B(3) Protection Against Physical Damage: SEC. Sched 80 PVC

Fastener spacing for cable–does that include SEC in PVC conduit?
230.51(A) Mounting Support: SEC. Max: 12" from ends and every 30"

Spacing for PVC. Does that include use for SEC?
352.30(A) Securing and Supporting: PVC. Within 3’ of outlet or term.
Table 352.30: Support 2.5" to 3" PVC every 6’

An electrician told me that 230.51(A) applies, but I say that assumes the cable is not in PVC conduit. I say 352.30(A) with its accompanying table applies even if it’s application is SEC. But I don’t see where the code explicitly says use the PVC rules for SEC, so I could be wrong.

Thanks in advance for sharing your expertise.


Is the run of PVC just used a sleeve or is it a complete conduit run?

I think it’s separate cables, so that would be a conduit. Would that change the fastener spacing?

Typically there is only one service cable to the house. Perhaps you mean conductors ?

A service riser run in PVC would use the spacing rules for PVC raceways. It does not matter the usage whether service or branch circuit .

Article 230 applies to services. It does not cover the installation requirements for service entrance cable. There is no way to fasten a cable inside a raceway . Article 338 covers the spacing of clamps for SE cables.

Complete raceway systems have specific requirements based on the type of raceway, sleeves on the other hand have no defined securing requirements so if you have a short section of raceway used as a sleeve the NEC is silent on how sleeves are to be supported. It would be up to the AHJ to decide if it’s supported properly. IMO if you followed the support section of the particular raceway code Article you would be OK.

Thank you Robert and Jim!


Greetings Robert,

From a “Cable” manufacturers perspective, if the cable is protected via a raceway then the rules of supporting and securing the “Cable” assembly takes precedence. In other words, if the raceway is not a complete run and you sleeve Type MC Cable in that raceway, we would expect it to be still secured and supported in accordance with section 330.30 and could careless about the “sleeve” from our perspective.

Please tell me how to secure SE cable every 30 inches that is in a PVC sleeve.

LOL…I don’t have too. I am just telling you the perspective of the Wire and Cable industry…Not that I agree with it…:wink:

People above me would say…small sleeves between straps every 30 inches…LOL

Remember Jim, I stated from a Cable Manufacturers perspective…not a Code Guys perspective.

Sounds like some good NEC 2020 Public Inputs…or to be honest I like it vague as expressed by Robert…personally.

Now Jim…we are going to tell the user to support and secure the Type SE in accordance with Part II of Article 334 when used as branch circuit or feeder applications. So we will give you 4 1/2’ to do your magic.

When you install it as actual service entrance cable as service entrance conductors and meeting the requirements of 230.51(A) then those rules will take over and the “or other approved means” can be the AHJ’s guide.

So many uses for Type SE Cable…just giving you a manufacturers perspective until which time someone puts in a PI otherwise.

Update : This looks like a potential Public Input - Thoughts for 2023 NEC

230.51 Mounting Supports. Service-entrance cables or individual open service-entrance conductors shall be supported as specified in 230.51(A), (B), or (C).

(A) Service-Entrance Cables. Service-entrance cables shall be supported by straps or other approved means within 300 mm (12 in.) of every service head, gooseneck, or connection to a raceway or enclosure and at intervals not exceeding 750 mm (30 in.).

Exception : Type SE cable shall be permitted to be unsupported at intervals exceeding 750 mm (30 in.) where protected against physical damage in accordance with 230.50(B)(1).

or something to that affect.

PS…I can only speak for the company I represent and we consider it “Supported” anytime it is installed in a raceway.

Nice to see an intelligent perspective from the manufacturer .

Actually Article 338 is rather silent on the spacing of clamps for SE Cable sad to say other than pushing you to 334.30 or 340.30. Kinda why I came to this thread and why all my other posts are on it. Yes someone sent it to me as I do not come here often anymore.

You are 100% correct…however 230.51(A) is demanding I secure it every 30 inches as I believe you expressed. So the NEC says you can sleeve it but then it doesn’t give you any relief from the rule to support it and for SE Cables article 338 is well…silent.

Ironically in a complete run (I believe someone mentioned) there is no need to secure or support it at all…or even connect it to an enclosure as one would think you do in 312.5(C).

Long story short…looks like a good set of proposals for the 2023 can be started and we are only 1/3 the way into the 2020.

Last Post because I just stopped by to say HI…but the problem with the theory of running a cable in a raceway, even for physical damage is that its all good when it is done horizontally and the cables are smaller…take this issue vertically and we see ISSUES even when it is sleeved much less a complete run.

My point is…the AHJ has to make this call and the manufacturers do not look at things always horizontally or vertically…so they are OVERLY protective of the cables for obvious liability reasons. The hidden truth is cables installed in raceways for the portion they are actually in the raceways are supported…but the way the NEC is written and the use of interpretation can cause the “wire and cable” industry to have a concern.

Ok…was nice chatting and I have been rambling (as you can tell)…I am off of this bad boy and will stop in to see you cats in a few months.