HST, VST
2.4 Electrical Connections
Connection by a qualified electrician is recommended.
The furnaces covered by this manual normally require a single phase A.C. supply, which may be
Live to Neutral non-reversible, Live to Neutral reversible or Live to Live. Some models may be
ordered for 3-phase use (and if so, are “universal” – see section 2.5).
Check the furnace rating label before connection. The supply voltage should agree with the
voltage on the label, and the supply capacity should be sufficient for the amperage on the label.
If the actual supply is not the same as the voltage on the label, then the controller power limit may
need to be adjusted: set the Heater Switch to off, connect the furnace and see section 3.6.
The supply should be fused at the next size equal to or higher than the amperage on the label. A
table of the most common fuse ratings is also given in section 8.1 of this manual. Where a supply
cable is present there are internal supply fuses: customer fusing is preferred but not essential.
Furnace with supply cable: either wire directly to an isolator or fit with a line plug.
Furnace without supply cable: a permanent connection to a fused and isolated supply should be
made to the internal terminals after temporary removal of the furnace back panel.
Connection by line plug: the plug should be within reach of the operator, and should be quickly
removable.
Connection to isolating switch: this should operate on both conductors (single phase) or on all live
conductors (three phase), and should be within reach of the operator.
The supply MUST incorporate an earth (ground).
CONNECTION DETAILS
supply type
Supply Terminal label Cable colour
Live-Neutral Reversible or Live-Live
1-phase
L Brown To live to either power conductor
N Blue To neutral to the other power conductor
PE Green/Yellow To earth (ground) to earth (ground)
supply Terminal label Cable colour
2- or 3-phase
L1 Black to phase 1
L2 Black to phase 2
L3 Black to phase 3 except 2-phase
N Light Blue to neutral except delta
PE Green/Yellow to earth (ground)
Do not connect a furnace ordered for three phase use to a single phase supply or to the wrong type
of three phase supply – except as indicated in sections 2.5 and 7.7.
2.5
“Universal Wiring” (year 2000 onwards)
When (and only when) ordered for 3-phase use these furnaces are supplied in a form in which they
can be easily rewired between 1-phase and 3-phase supplies. This applies to 3-phase+N and 3-
phase delta in the ranges 380/220V–415/240V and 200-240V, but does not apply to 3-phase star
without neutral (e.g 380V or 440V).
To alter the configuration, remove the control box back panel and alter the connections between
the supply terminal block and the EMC filters, using the appropriate diagram from section 7.7.
Models ordered for single phase only are not affected and cannot be converted to 3-phase.
If in doubt, please consult Carbolite.
3.0
4 MF13
