Choc blocks and rust

[Graham_Wright]

As a matter of course, I replace the screws, which I have always found to be steel, with stainless.

Just had the bill for 100 M4 X 12 A2 socket head - £2!

(If the brass "lump" isn't M4, tap it M4 with a cordless drill.)

 

[PaulRainbow]

Or throw it overboard and use a proper junction block

May i suggest something such as this : https://www.12voltplanet.co.uk/bluesea-systems-20a-terminal-block-6-way.html

No need to buy screw, no need to tap holes. Choc blocks require crimping bootlace ferrules to the wires, may as well crimp some rings on and use these.

 

[rogerthebodger]

Or throw it overboard and use a proper junction block

May i suggest something such as this : https://www.12voltplanet.co.uk/bluesea-systems-20a-terminal-block-6-way.html

No need to buy screw, no need to tap holes. Choc blocks require crimping bootlace ferrules to the wires, may as well crimp some rings on and use these.

Or use a choc block that includes a leaf spring to prevent damage to the wire strands

 

[Graham_Wright]

Or throw it overboard and use a proper junction block

May i suggest something such as this : https://www.12voltplanet.co.uk/bluesea-systems-20a-terminal-block-6-way.html

Screw material? Not stated. Why two screws? One should be sufficient. Messy to cut to length - the fixing holes are at the end.

And, of course, considerably cheaper.

No need to buy screw, no need to tap holes. Choc blocks require crimping bootlace ferrules to the wires, may as well crimp some rings on and use these.

Yes - I use bootlace ferrules.

 

[pvb]

Or use a choc block that includes a leaf spring to prevent damage to the wire strands

Yes, the Blue Sea "Euro Style" terminal blocks have a stainless leaf to clamp the wire, nickel plated brass body and nickel plated brass screws.

 

[PaulRainbow]

Yes, the Blue Sea "Euro Style" terminal blocks have a stainless leaf to clamp the wire, nickel plated brass body and nickel plated brass screws.

100% improvement on Screwfix type chock blocks. I'd still crimp ferrules on though.

 

[Martin_J]

I wonder if these are Blue sea ...

https://www.furneauxriddall.com/acatalog/Screw-Connector-Block---6-Way-VA_188_6.html

They're what I've been using...

 

[PaulRainbow]

Screw material? Not stated. Why two screws? One should be sufficient. Messy to cut to length - the fixing holes are at the end.

And, of course, considerably cheaper.





Yes - I use bootlace ferrules.

Screw material will be non-ferrous, they are Bluesea.

One screw for each wire, same as your choc blocks.

As for cutting to length, you don't, you buy the correct length.

Additional benefit is the ability to add links to make groups of wires.

Wasn't meant to be a negative/critical post Graham, just pointing out an alternative. Others have brought the Bluesea strip connectors to the table too. All useful info IMO :encouragement:

 

[rogerthebodger]

I'd still crimp ferrules on though.

The use of a crimp ferrule would create a hard spot on the leaf blade that would derate the current capacity.


From the bluesea web site

http://assets.bluesea.com/files/resources/newsletter/page_113.pdf

• Stainless Steel pressure plates meet ABYC requirements for stranded
wire connections without the use of crimp-on terminals
• Strips are easily cut to required length
• Screw and pressure plate construction meet ABYC pull-out strength
requirements

 

[rogerthebodger]

Screw material will be non-ferrous, they are Bluesea.

One screw for each wire, same as your choc blocks.

As for cutting to length, you don't, you buy the correct length.

Additional benefit is the ability to add links to make groups of wires.

Wasn't meant to be a negative/critical post Graham, just pointing out an alternative. Others have brought the Bluesea strip connectors to the table too. All useful info IMO :encouragement:

One other advantage is that the ring connector will not fall off if the screw comes loose, would need the screw to fall out for that to happen.

I much prefer the type with a screw coming out of the block that a nut is used to clamp the ring. I have only seen these in the bigger current sizes so I tend to make my own with either brass strips or HDPE strips and plated brass screws depending in common or insulating connectors are needed.

 

[LadyInBed]

I'd still crimp ferrules on though.

I don't, I strip back the wire, fold the stripped wire back over the sleeve and put that into the terminal block with the sleeve side up to the screw, then screw down onto the sleeve.
PS Makes for a good electrical and​ mechanical anti-vibration connection.

 

[PaulRainbow]

The use of a crimp ferrule would create a hard spot on the leaf blade that would derate the current capacity.

I don't believe that to be correct. The ferrule would be firmly pressed against the body of the terminal.

Plenty of information on the net regarding ferrules, so i'm not going to spend time explaining the benefits (be like re-inventing the wheel). EU CE certification requires their use, so i doubt they are a bad thing.

For instance : http://www.ee.co.za/article/ferrules-insurance-connection-failure.html

 

[PaulRainbow]

I don't, I strip back the wire, fold the stripped wire back over the sleeve and put that into the terminal block with the sleeve side up to the screw, then screw down onto the sleeve.
PS Makes for a good electrical and​ mechanical anti-vibration connection.

http://www.ee.co.za/article/ferrules-insurance-connection-failure.html

 

[LadyInBed]

http://www.ee.co.za/article/ferrules-insurance-connection-failure.html

Good article, but doesn't address the method that I described!
Stripped wire folded back over insulation and fitted as described gives the properties of a solid connection.

 

[rogerthebodger]

Good article, but doesn't address the method that I described!
Stripped wire folded back over insulation and fitted as described gives the properties of a solid connection.

I also use that method sometimes with small wires.

Interesting that the company the writer works for Weidmüller states the method to wire up their terminals

1) cut wire to length
2) strip the wire
3) connect the wire



https://b2b.weidmuller.com/marshalling/docs/index/LIT1021_WMF2.5_Terminals_Brochure.pdf
Page 3

No talk about crimps of any kind.

 

[PaulRainbow]

I also use that method sometimes with small wires.

Interesting that the company the writer works for Weidmüller states the method to wire up their terminals

1) cut wire to length
2) strip the wire
3) connect the wire



https://b2b.weidmuller.com/marshalling/docs/index/LIT1021_WMF2.5_Terminals_Brochure.pdf
Page 3

No talk about crimps of any kind.

You are quoting from a brochure for their WMF2.5 terminal system. You quote if from their descriptions comparing using screw connections and their system, using ready made cables. It insn't a set of instructions or recommendations. It's clear to see they recommend ferrules from the earlier article i linked to. It's also a CE certification in Europe.

Given the use to which we are putting our connections, the following paragraph seems pretty relevant :

The long-term electrical performance is also higher because ferrules, applied with the proper crimping tool, form a gas-tight connection shielding the wire from corrosion even in a salty environment. “Gas tight” refers to the ability of air or other gases to permeate the connection.

At the end of the day, we can all choose to use whatever we like to connect our wiring. I choose to use quality terminals and industry standard best practice, which includes ferules.

 

[rogerthebodger]

The terminals I quoted have a "clamping yoke" so the screw does not bare on the wire unlike normal choc blocks.

The choc blocks I use have a leaf spring between the screw and the wire so again the screw does not bare on the wire.

If I was to use a choc block without a leaf spring I would use a pin crimp so the wire cannot get damaged.

To me quality terminals either a clamping yoke or a leak spring to protect the wire and eliminate the requirement for a pin crimp that cuts assembly time and cost in a production situation.

Cheap choc blocks with only a screw to clamp the cable has no place anywhere but tend to be supplied as they are cheap.

 

[PaulRainbow]

The terminals I quoted have a "clamping yoke" so the screw does not bare on the wire unlike normal choc blocks.

The choc blocks I use have a leaf spring between the screw and the wire so again the screw does not bare on the wire.

If I was to use a choc block without a leaf spring I would use a pin crimp so the wire cannot get damaged.

To me quality terminals either a clamping yoke or a leak spring to protect the wire and eliminate the requirement for a pin crimp that cuts assembly time and cost in a production situation.

I understand what you're saying Roger, but i do feel the crimp is still better, even with the connectors that you use. I've just installed some Garmin electronics and they use the same style of connectors as you, but crimp ferules on, as i do.

Cheap choc blocks with only a screw to clamp the cable has no place anywhere but tend to be supplied as they are cheap.

Totally agree with you there.

 

[penberth3]

...Cheap choc blocks with only a screw to clamp the cable has no place anywhere but tend to be supplied as they are cheap.

Useful to have a few around for emergency repairs?

 

[icarusbop]

I use WAGO connectors, either 222 or 221 depending on the current required. You don't need a screwdriver for them and they are re-useable. They fix to the wires very securely and different sized wires are easy to connect.
I don't know if they are stainless, but I've got a few in use that are not showing any signs of corrosion.
Perhaps not ideal for critical applications, but for general wiring they are great and very easy to replace / refit if required at sea and in bumpy conditions.
you can find them all over, but a quick search on popular auction sites for Wago 221 / WAGO 222 will point you in the right direction.
WAGO also make mounts and other fittings If you need them to be secured to bulkheads etc.

edit: I've just found this on the spec sheets "Tinned current bars ensure a permanent, gas-tight and secure wire connection."