What's new
What's new

Wire Ferrules- When to use or not use?

Cole2534

Diamond
Joined
Sep 10, 2010
Location
Oklahoma City, OK
In instrument panels I pretty much ferrule everything, but is there a reason NOT to use them in a breaker panel or disconnect? Surely a properly crimped ferrule won't limit current, or cause an unsafe condition, right?

These would be 8 & 10 AWG MTW conductors.
 
First to look for, are the ferrules U/L or equal listed or recognized? So long as the ferrule is properly assembled per the instructions, it should be just fine. The only advantage that I see is keep the individual wire strands neat and orderly. They do introduce one additional element in the current path, and if they are not properly assembled, may cause a loose joint. Recall that panels have wired with stranded wire for over a 100 years quite satisfactory. Unless a joint is taken apart frequently, I see no advantage.

Tom

If wires are cut and terminated automatically as on an Artos this could prevent strands from splaying.

T:-
 
Using Knipex crimpers on a quality ferrules, so that shouldn't be an issue.

I like them because they keep things tidy and I feel like the panel lugs get a better bite on them.

Sent from my SM-G973U using Tapatalk
 
The 508A only states that ferrules have to use a crisper approved by ferrule manufacturers. Also for reasons unknown they do not allow for use of ferrules on existing equipment in the field
 
Also for reasons unknown they do not allow for use of ferrules on existing equipment in the field
That is interesting, I had never heard that

I ferrule most wires up to 14 awg. When deciding whether to ferrule or not, my two main considerations are neatness and whether it would be easy for a single strand of one wire to get into the next during component changes.

I'm debating on getting an automatic ferrule machine. If I do then I would probably ferrule most every wire.
 
By automatic ferruling machine, is this one the cuts, strips the insulation and assembles the ferrule? Is there room for two ferrules in a saddle clamp termination? Ring and spade terminates are commonly stacked in such cases, but the plastic sleeve may cause interference side by side.

If you want to go to the expense of a terminating machine, why not fuse the wire with resistance welder (Joyal fuser, About Joyal) or equal machine. I have used Joyal welders in my designs and they work very well. These machines can be incorporated into an automatic termination machine or stand alone. Better yet, this eliminates a part and eliminates a potential problem area, a bad crimp or no crimp.

Tom
 
By automatic ferruling machine, is this one the cuts, strips the insulation and assembles the ferrule? Is there room for two ferrules in a saddle clamp termination? Ring and spade terminates are commonly stacked in such cases, but the plastic sleeve may cause interference side by side.
I didn't think the dual ferrules were allowed by UL

If you want to go to the expense of a terminating machine, why not fuse the wire with resistance welder (Joyal fuser, About Joyal) or equal machine. I have used Joyal welders in my designs and they work very well. These machines can be incorporated into an automatic termination machine or stand alone. Better yet, this eliminates a part and eliminates a potential problem area, a bad crimp or no crimp.

Tom
That's pretty neat. I hadn't seen one of them. I have a machine that cuts wire to length and strips both ends. It has been well worth it. It can do about 1 hours hand cutting in stripping per minute of run time. Installing ferrules would be a nice addition.
 
What machine did you get for cutting and stripping? The ferrules that I use (Wago) has a ferrule that is designed for 2 wires great for my strain gauges where we have a jumper wire.
 
I avoid using ferrules that have plastic ends that cover the insulation. They add no value other than beauty and often they get in the way. I try to use plain tube ferules because they allow multiple connection cycles without damaging the wire.
 
What machine did you get for cutting and stripping? The ferrules that I use (Wago) has a ferrule that is designed for 2 wires great for my strain gauges where we have a jumper wire.
Here is the machine I have.
https://www.amazon.com/dp/B073ZD7FQR/ref=cm_sw_em_r_mt_dp_T1XCJYB342W32GZ4J9VM

If you don't need the wires stripped, it can actually multiple small wires at the same time. Here's a sample of that.
Wire machine cutting multiple wires

Here it is cutting and stripping
Wire machine cutting and stripping

In both cases it is running half speed. Any faster than that and you start loosing coordination trying to bag the wire.
 
Last edited by a moderator:
Moderately on topic, does anyone have a favorite panel wire? 16ga, 120vac/24vdc.
If we're talking UL, then your 120VAC would need to be 14AWG minimum. After a class 2 power supply then UL doesn't have any requirements and I usually use 18AWG, mainly because it can fit into small terminals even when ferruled.

As far as wire type, I use MTW because it is flexible and lays really well in wire duct, even 4/0 is manageable. I've got a video on it too on my channel but I don't want to seem spammy by keeping on posting links. Just look for the control panel building series.
 
If we're talking UL, then your 120VAC would need to be 14AWG minimum. After a class 2 power supply then UL doesn't have any requirements and I usually use 18AWG, mainly because it can fit into small terminals even when ferruled.

As far as wire type, I use MTW because it is flexible and lays really well in wire duct, even 4/0 is manageable. I've got a video on it too on my channel but I don't want to seem spammy by keeping on posting links. Just look for the control panel building series.

I don't believe U/L has anything to say in this area. They go by temperature tests. The old JIC standards did require a minimum of 14 ga, but that is the only one I am aware of. I don't think I have seen a modern (last 60 years) NEMA starter wired with 14 ga, I know all the GE starters were 16 ga.

Tom
 
I don't believe U/L has anything to say in this area. They go by temperature tests. The old JIC standards did require a minimum of 14 ga, but that is the only one I am aware of. I don't think I have seen a modern (last 60 years) NEMA starter wired with 14 ga, I know all the GE starters were 16 ga.

Tom

UL 508A states the following, this is for control panels, interestingly components such as that GE starter don't follow UL 508A.

Power wiring - "29.6.1 Internal wiring of a power circuit shall not be smaller than 14 AWG (2.1 mm2) and..."

Control wiring - "37.2.1 The required size of a field wiring terminal for a control circuit shall not be less than 14 AWG"

Control circuits can also use Table 37.1 to lower the wire size, but there are special markings required, usually I use a class 2 power supply at this point so it isn't an issue.
 
UL 508A states the following, this is for control panels, interestingly components such as that GE starter don't follow UL 508A.

Power wiring - "29.6.1 Internal wiring of a power circuit shall not be smaller than 14 AWG (2.1 mm2) and..."

Control wiring - "37.2.1 The required size of a field wiring terminal for a control circuit shall not be less than 14 AWG"

Control circuits can also use Table 37.1 to lower the wire size, but there are special markings required, usually I use a class 2 power supply at this point so it isn't an issue.

I concede to 29.6.1 for POWER wire and yes, the opening statement was about 8 and 10 ga. I was thinking about the control wire. The next point is for field wiring (customer) connectors. Here the size of the connector was always larger than required. For instance, the size of power terminals of the size one were good for from 14 to 8 ga as I recall.

Everybody in the US industrial controls market, GE (now ABB), AB (Rockwell), CH (Eaton), SqD (Schnieder), Westinghouse (CBS Corp)...follows 508.

Tom
 
I avoid using ferrules that have plastic ends that cover the insulation. They add no value other than beauty and often they get in the way. I try to use plain tube ferules because they allow multiple connection cycles without damaging the wire.

+1 on avoiding ferrules with insulation - I've had cases where the screw contact would just about bear on the metal, but
was partly bearing on the insulation. Works for a while, then it doesn't.
 
I had to look up some other things in UL 508A so I went ahead and found the details of the ferrule specification while I was at it.

First I was wrong about the multiple wire ferrules not being allowed, I'm not sure where I got that idea. I interpret B below to say you can.

29.3.6 A wiring ferrule shall be:
a) Used with stranded copper wire(s) only;
b) Terminated in a connector rated for copper wire and rated for the number and size of wire(s) crimped to the ferrule;
c) Crimped with an appropriate tool as recommended by the ferrule manufacturer before terminating in a terminal of a component;
d) Sized in diameter appropriate for the number of wires and wire size(s) as recommended by the ferrule manufacturer; and
e) Crimped to the wires such that the length of the uninsulated portion of the wires does not result in the reduction of electrical spacings when the ferrule is installed.

UL does specify that ferrules should or should not be used, also they say nothing of insulated vs non insulated ferrules. Personally I use insulated ferrules but honestly that is just a personal preference.

The only other item of interest is that UL states that ferrules do not affect the short circuit current rating of the panel.

This might make a good video idea, I'll let you know if I do.
 
Wouldn't that mean you were using the wrong length of ferrule?

In this case they were crip-on terminals like ferrules, going into a DIN rail device. Opening the screw
terminal all the way permitted the insulation to *just* get caught by the terminal, this worked for quite
some time before it magically went open one day. Leading to some severe head-scratching.

Took me a bit of time to trace down what the manufacturer had done.
 








 
Back
Top