Garage door power

[caseyjones1961]

I had to relocate the fused spur for my electric garage door, l went to switch out the power and was surprised to find the spur is on the the mcb as the garage lights....is this normal and above all else...safe?

 

[ban-all-sheds]

Normal is for people to use a source of power which is most convenient.

As long as the load of the motor is not too high for it to go on a lighting circuit it is quite safe. Do you know what the load is? What's the rating of the fuse in the FCU?

 

[John D v2.0]

yes there's no reason why not, assuming it meets disconnection times and current carrying capacities. The main problem is labelling of circuits, which should be clear and unambiuous

 

[caseyjones1961]

Thanks chaps...that's reasurring, been like that for years with no issues, just wanted to check.

 

[ban-all-sheds]

What's the rating of the fuse in the FCU?

FYI - if it's on a lighting circuit chances are you don't need an FCU, although you might like to keep a means of double-pole isolation.

 

[winston1]

As it is on the lighting circuit the FCU is not required. It will offer no discrimination with the circuit MCB.

 

[ericmark]

As it is on the lighting circuit the FCU is not required. It will offer no discrimination with the circuit MCB.

It would depend on fuse in the FCU and the type of MCB plus type of fault. Some doors are 12 volt the idea is they can be opened even if there is a power cut, clearly required with integral garages with no personal door.

Even with 1A fuse which is the smallest one can normally get for FCU with a short circuit a B6 MCB will still trip first, however other overload faults likely fuse will blow before trip goes.

With a battery powered unit, be it garage door or stair lift, the power required is very low, some where around 20W and unlikely to exceed 50W, with direct mains powered doors however likely a lot higher, around 200W.

Although direct powered units could draw extra power if for example water in tracks has frozen causing a 1A fuse to rupture both saving lights going out and motor being damaged, with the battery backed type it is unlikely any fault will cause an overload on the mains supply. Maybe a faulty rectifier or battery may cause an overload, but for a fuse to protect it would need to be carefully selected, so a 0.63 amp fuse on the circuit board may offer some protection, but the type of fuse found in a FCU is unlikely to protect from this type of fault.

However although items considered as portable the fuse in the plug is only for the cable, with fixed items the manufacturer can stipulate an external protection device, it is common for boilers to require a 3A fuse in a FCU.

I have never tried a 5 amp fuse with a 6 amp D type MCB, not sure which would open first, but have had the 3A fuse fitted inside a fluorescent lamp rupture before the B6 MCB so even a 3A fuse can help.

 

[EFLImpudence]

with fixed items the manufacturer can stipulate an external protection device, it is common for boilers to require a 3A fuse in a FCU.

It is common that it is stated. Require is a different matter.

"Vous devez installer une unité de raccordement à fusible 3A pour cette chaudière."

"Qu'est-ce que c'est. Je n'ai jamais entendu parler d'une telle chose."

"Alors, vous ne pouvez pas avoir de chaudière."