Brass bolts? Avoiding bi-metal corrosion on SWA glands

Brass bolts? Avoiding bi-metal corrosion on SWA glands

Author
Discussion

jakesmith

Original Poster:

9,461 posts

170 months

Thursday 26th May 2022
quotequote all
There’s a junction box outside that has SWA glands

There is severe corrosion where the non-brass crimp contacts the earthing nut inside the box, and the supplied screw in the earthing nut is also badly corroded.

so I’m planning on replacing them, how do I avoid this corrosion? Surely it’s caused by 2 different metals in contact. Are there brass crimps?

It looks like everything was installed as per the kit. Confused.




Edited by jakesmith on Thursday 26th May 23:52

smifffymoto

4,527 posts

204 months

Friday 27th May 2022
quotequote all
I would sack that off and get a gland kit with the ring type earth,the type that is between the gland and your adaptable box.

21TonyK

11,494 posts

208 months

Friday 27th May 2022
quotequote all
Duralac? Don't know enough to know if it would solve the problem.

jakesmith

Original Poster:

9,461 posts

170 months

Friday 27th May 2022
quotequote all
smifffymoto said:
I would sack that off and get a gland kit with the ring type earth,the type that is between the gland and your adaptable box.
Might sound like a stupid question but I have those too and same issue - the nut and bolt I used to connect the ring to the crimp has badly corroded. What type of nut and bolt should I use? Think I used stainless steel as I had some on hand that fitted, guessing that’s the issue.

EddyP

846 posts

219 months

Friday 27th May 2022
quotequote all
Use a brass nut and bolt.

If the nut holding the glad to the JB inside is corroding badly then your JB is probably getting water inside it.

sospan

2,469 posts

221 months

Friday 27th May 2022
quotequote all
Clean the connection, refit, put petroleum jelly over it.
Thiss has been the go-to on cars for decades.
Battery terminals and earth connections in particular.

jakesmith

Original Poster:

9,461 posts

170 months

Friday 27th May 2022
quotequote all
smifffymoto said:
I would sack that off and get a gland kit with the ring type earth,the type that is between the gland and your adaptable box.
Might sound like a stupid question but I have those too and same issue - the nut and bolt I used to connect the ring to the crimp has badly corroded. What type of nut and bolt should I use? Think I used stainless steel as I had some on hand that fitted, guessing that’s the issue.

Yabu

2,052 posts

200 months

Friday 27th May 2022
quotequote all
jakesmith said:
There’s a junction box outside that has SWA glands

There is severe corrosion where the non-brass crimp contacts the earthing nut inside the box, and the supplied screw in the earthing nut is also badly corroded.

so I’m planning on replacing them, how do I avoid this corrosion? Surely it’s caused by 2 different metals in contact. Are there brass crimps?

It looks like everything was installed as per the kit. Confused.




Edited by jakesmith on Thursday 26th May 23:52
The gland you have linked to is an indoor gland, is that what you have outside?
External glands have a rubber seal that goes over the outer sheath of cable to seal it.

Belle427

8,858 posts

232 months

Friday 27th May 2022
quotequote all
Is the junction box rated for being outside?
As suggested use exterior glands and the correct junction box and all should be well.

Gooose

1,443 posts

78 months

Friday 27th May 2022
quotequote all
You could replace and wrap in a little denso tape, no moisture will get at it then, or chuck a few silica bags in the box

jakesmith

Original Poster:

9,461 posts

170 months

Friday 27th May 2022
quotequote all
Thanks all, seems my issue is inadvertently using internal gland kits, using stainless bolts.
The junction box has the correct IP rating
I will replace following the suggestions above

smifffymoto

4,527 posts

204 months

Saturday 28th May 2022
quotequote all
If you use denso be careful,it can be messy.