Correct installation MCB's

[Bendesa1962]

Hi everyone

I've a question about installing and connecting MCB's. It's my understanding that you always install the incoming wire at the top of the MCB and outgoing at the bottom. Can it cause any problems if you switch these?

I've an installation from a client who did the install himself. The wire comes from a Outback Chargecontroller FlexMax 80 and goes to a battery bank. He connected the incoming at the bottom and outgoing on the top. It did run fine for over 2.5 months and today the wire did start burning and also the MCB did not trip. Anybody any idea?

Thx

[SunEagle]

Hi everyone

I've a question about installing and connecting MCB's. It's my understanding that you always install the incoming wire at the top of the MCB and outgoing at the bottom. Can it cause any problems if you switch these?

I've an installation from a client who did the install himself. The wire comes from a Outback Chargecontroller FlexMax 80 and goes to a battery bank. He connected the incoming at the bottom and outgoing on the top. It did run fine for over 2.5 months and today the wire did start burning and also the MCB did not trip. Anybody any idea?

Thx

Electrical wire burns can happen for a couple of reasons. Remember the Circuit Breaker is there to protect against a dead short or high current spike but not necessarily for high currents over a long period of time. Wire insulation tends to burn when it is exposed to high currents or loose connection. Both of these can cause the wire to see high temperatures that exceed the insulation rating.

If it was me I would first check the connections to see if they are tight. I would also make sure the connections are acceptable for the wire metal type (aluminum or copper). Next I would use a clamp on meter to check the current going through the wire. If it exceeds the wire rating for a period of time you will have to either up size the wire or lower the current going through it.

And finally I would have someone with electrical experience to check all of the system wiring. An off grid solar/battery system that back-feeds a MCB might not be correct per code or safety rules.

[Weldman]

Supply in the bottom, load out the top.