Could someone help with the age of this DB?

[TheCodboy]

Hi all, my friend has just moved into a property and I've had a quick look at his DB and was greeted with a very old Crabtree board. Could someone give a rough estimate on how old it is? I think it could be one of the oldest ones I've seen. Thanks in advance!!

 

[westward10]

Crabtree C50 consumer unit they are quite rare, C50 tended to be commercial not Milton Keynes by any chance. 1980s though.

 

[TheCodboy]

Crabtree C50 consumer unit they are quite rare, C50 tended to be commercial not Milton Keynes by any chance. 1980s though.

It's in a house in North Tyneside (near Newcastle upon Tyne). Does this board predate the old rewire able fuseboards??

 

[nicebutdim]

Weren't C50 breakers in procuduction much earlier than the 80s?

 

[TheCodboy]

Weren't C50 breakers in procuduction much earlier than the 80s?

By the look of it,I think Noah had one on the Ark....

 

[westward10]

Weren't C50 breakers in procuduction much earlier than the 80s?

Yes would have been late 70s I probably should have said late 70/80s.

 

[Lucien Nunes]

Late 60s-70s. Crabtree C50 series, magnetic-hydraulic MCBs. Still in use in certain places e.g. London Underground. There are older designs of MCBs than those.

 

[nicebutdim]

Quick google search suggests C.50 range introduced in 1960 and Crabtree logo changed to that still used today in 1970.

That would seem to date this board somewhere in the 60s.

 

[TheCodboy]

Quick google search suggests C.50 range introduced in 1960 and Crabtree logo changed to that still used today in 1970.

That would seem to date this board somewhere in the 60s.

Wow.... That could tie in with the original build date of the house. Amazing

 

[westward10]

Being a consumer unit I would put it early 80s but could be wrong.

 

[nicebutdim]

Being a consumer unit I would put it early 80s but could be wrong.

Who knows when something might make its way from a distributor to a building, but logo change in 1970 seems likely to place it a bit earlier.

 

[westward10]

They are unusual in that they don't use thermal principles for overcurrent, both fault and overcurrent are magnetic.

 

[Lucien Nunes]

Indeed. They have a little sealed hydraulic capsule inside the coil. When overcurrent is present, magnetic flux from the coil creates enough force on the ferrous piston inside to overcome a spring, causing it to move slowly against fluid resistance towards one end of the cylinder. As it moves, it changes which part of the core it magnetically shunts, and in its final position it increases the flux acting on the tripping armature enabling the amount of flux already present to trip the breaker. This creates the timed response normally associated with the thermal element of an MCB. If a fault occurs, there is enough flux to cause the armature to trip the mechanism instantly, without having to wait for the hydraulic unit to respond.

 

[Dave OCD]

Indeed. They have a little sealed hydraulic capsule in the magnetic circuit. When overcurrent is present, magnetic flux from the coil creates enough force on the ferrous piston inside to overcome a spring, causing it to move slowly against fluid resistance towards one end of the cylinder. When it gets there, its position decreases the magnetic reluctance of the circuit enabling the amount of flux already present to operate the tripping armature. This creates the timed response normally associated with the thermal element of an MCB. If a fault occurs, there is enough flux to cause the armature to trip the mechanism instantly, without having to wait for the hydraulic unit to respond.

They must have been relatively expensive at the time ?

 

[Lucien Nunes]

I have some prices somewhere but yes. Hence most of these being found in commercial and industrial boards, with much less uptake into domestic where the additional cost over fuses wasn't thought justfied. These plastic-fronted domestic boards are relatively rare. Someone (Tel? Gerry?) on the forum kindly sent me one for the museum a few years ago.