no power to fryer

[tonto33]

hi
Been called out to look at fault in kebab shop, there chip fryer is hard wired to 45a sw & neon that lost power, removed switch and found no power getting to it, checked the cu and all the mcb are still in the up position, the fryer is wired to 32a mcb which didnt trip, it is a double fryer that each side is wired to its own 45a switch, disconnected from the faulty sw and wired into the other sw and fryer worked for both sides, when wired both sides into the working switch to check out the fryer it seemed to work for 10 mins then blew the trip, so where do i need to be looking at to find why the no power getting to the switch?

 

[Sparky Ninja]

What are the loads of these fryers?
Was the other fryer working when you arrived or was the supply isolated to both?

It could be an overload with the MCB operating but the switch not moving, it can happen.

Is there any sign of burning within the switch connections?

 

[tonto33]

the fryer is 9kw x2 when got there one side was working which was wired into it own 45a sw the other side was not working and had no power to the switch, there was no signs of burning to the switch connections all seems fine.
it one of these fryers Lincat DF618 Counter Top Fryer

 

[telectrix]

probably burnt the MCB out. replace both. what cable size is it feeding the 45A switches. if it's 6mm and clipped direct or otherwise not subject to a derating factor, replace the 32A MCBs with 40A. not surprised the 32Atripped with both fryers on it.i w

ould also measure the current drawn. around 40A, which is close to the max. for 6mm.

 

[tonto33]

thanx will try that when go back tomorrow, one other question roughly how much to charge to fit mcb's

 

[telectrix]

don't just fit willy-nilly. at 40A load the cable needs checking for size. 6mm is minimum. measure the current drawn. a 32A will stand 40A for short periods. ask how long the MCBs have been in service. if its years as opposed to months, you can probably just replace with same rating. if you have an old board, the MCB scould be obsolete and replacements can be expensive e.g. £12 as opposed to £3 for current types. also make sure they're not RCBOs as these cost even more. cost the parts and bill for parts + 30%, and add labour at your normal rate . me, i would charge £40 + £15 per half hour after the first hour.

 

[Marvo]

I would run an insulation test on the fryer. Grease and dirty oil can cause an earth fault if it's in the components or caked on the ends of the elements. The rise in temp as the fryer warms up can increase the likelyhood of arc flashing over the oil. Dig out the Mega Tester before you blow another MCB would be my advice and run the same tests with the fryer cold and warm as well.