Help with amp limits for direct burial kit

Status
Not open for further replies.
S

sparrott4

Member
I'm a little confused. I'm evaluating a 3M DBY Direct Burial Splicing Kit for use with low voltage lighting. The kit contains a gel sealant and wire connector. The kit is rated for 30 volts (another is rated for 300 volts). I've been through the specs carefully and there's no rating for maximum amperage.

In the past I've heard that some gel-filled wire nuts are only good up to 15 amps. An lv system run can go up to 25 amps, so I'm wondering how to know if the 3M kit will be up to the task.

Any help?

Here's the product link: http://multimedia.3m.com/mws/mediaw...Y0YOY9Tfwvrfdv_IwUTfwUTfTTTTTT--&fn=DBYDS.PDF
 
I rarely if ever see a current rating for a terminal.

I think it is assumed the terminal can handle the current that the conductors rated to fit it can carry.
 
Maybe I'll answer my own question with an assumption. In their instructions, they give typical wire combinations - the largest one being (2) #12-2, that has an amp max. of 16 amps. Can we assume they wouldn't suggest a wire type that could exceed max. amps for the grease?
 
I would agree with Bob's assumption, if the conductor fits in the terminal it should be rated for the ampacity of that condcutor.
 
Determining ... 110.15(B)(1)... and it under Splicing. (a good read in itself):)

Well, one has to remember what your looking for or at.

I'm not exactly sure of what your doing with the numbers presented, and whatever product your using IE the circuit.

A lot of us don't usually drop out of T 310.16, but since your are, you might be able to go to T 310.13 and Article 720 for low voltage. Get back to me later after the reading of those links...

A good mental review could also include reading all the items under Circuit in the index, a lot will be within 720.

Is there a UL listing on any of the products in this project? :) You could read more about it from the number with their seal on the product, hopefully on cut sheet also.

Sorry to lecture, I know you want to make a splice and go on... but . . .
 
Last edited:
cadpoint said:
Determining ... 110.15(B)(1)... and it under Splicing. (a good read in itself):)

Well, one has to remember what your looking for or at.

I'm not exactly sure of what your doing with the numbers presented, and whatever product your using IE the circuit.

A lot of us don't usually drop out of T 310.16, but since your are, you might be able to go to T 310.13 and Article 720 for low voltage. Get back to me later after the reading of those links...

A good mental review could also include reading all the items under Circuit in the index, a lot will be within 720.

Is there a UL listing on any of the products in this project? :) You could read more about it from the number with their seal on the product, hopefully on cut sheet also.

Sorry to lecture, I know you want to make a splice and go on... but . . .
Click to expand...

What about Article 411?
 
Ok I have heard term like how many amps the grease (post 3) can handle, how many amps can a twist on wire nut can handle (Post 1), the answer to this is simple, none, it is not the wire nut or the grease that handles the current, it is the connection between the wires that make the connection that handles the amps, the grease is just there to seal out any moisture to prevent corrosion, and the wire nut is there to hold the connection together, the little spring in the wire nut is not designed to carry current, and when they do they will burn up even under a lightly loaded connection.

There are some splice connectors with set screws that do carry the current but I would say that these are very specific on wire size and would believe that they would be rated for the largest wire they are rated for.
 
Last edited:
infinity said:
What about Article 411?
Click to expand...

It's listed in Article 720, thanks for pointing out that!

I just don't think the OP is matching all of what required in 411.

If he has a 15 amp jelly wire nut and the circuit that hold 25 amps, that can use up to 25 amps
mind you, which gives or why even worry about a max 20 amp breaker, per the article?

The question should have been is a 30V or 300V splice good for 600V wire?

I realize the numbers are high in respects to a the real amp draw or even in real practice, but what of the wiring and it's rating?
 
hurk27 said:
Ok I have heard term like how many amps the grease (post 3) can handle, how many amps can a twist on wire nut can handle (Post 1), the answer to this is simple, none, it is not the wire nut or the grease that handles the current, it is the connection between the wires that make the connection that handles the amps, the grease is just there to seal out any moisture to prevent corrosion, and the wire nut is there to hold the connection together, the little spring in the wire nut is not designed to carry current, and when they do they will burn up even under a lightly loaded connection.

There are some splice connectors with set screws that do carry the current but I would say that these are very specific on wire size and would believe that they would be rated for the largest wire they are rated for.
Click to expand...

I understand that the grease and wire nut don't carry the current. The issue with grease-filled wire nuts is the heat generated by the wire. It's a known problem that grease can melt and leach out of a connector when heat is too high. Having stated this, I guess my question about amp limits is pretty stupid. I suppose it's a better question to ask how hot wires can get when heavily loaded? Then, at what temperature does the gel melt.

The 3M specs don't give a melting point for the gel - just a max operating temp of 120F.
 
sparrott4 said:
I understand that the grease and wire nut don't carry the current. The issue with grease-filled wire nuts is the heat generated by the wire. It's a known problem that grease can melt and leach out of a connector when heat is too high. Having stated this, I guess my question about amp limits is pretty stupid. I suppose it's a better question to ask how hot wires can get when heavily loaded? Then, at what temperature does the gel melt.

The 3M specs don't give a melting point for the gel - just a max operating temp of 120F.
Click to expand...

Reread the specs.

Operating Temperature: 221?F to ?40?F
(105?C to ?40?C)
 
Status
Not open for further replies.
Top